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Description Dave, an ambitious researcher at a well-known university, hires an eager-to-grow football player to test an experimental growth supplement. The experimental growth supplement works much better than anticipated and Grunt gains over 50 pounds in just a week, though with some troubling side-effects.

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Updated22 Dec 2017
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Part 1

Dave slumped over his computer. His eyes flicked to the clock on the desktop—7pm—and he groaned. It was going to be another late night. A gifted research talent, he had worked at DARPA since he was 22, but after six years of government oversight, he threw in the towel and started working at a public university. He was the youngest professor in the department, but he hadn’t expected there to be so many late nights. Grading, lesson planning, and keeping up with his research was proving to be really difficult. It didn’t help that his current research project had hit a brick wall with no foreseeable way around it.

Well, that wasn’t exactly true. He knew his formula worked… in animal models. The results had been truly impressive with the mice he had been working with for the past year. He looked over at the enormous mouse in the cage next to him. People on the outside would be shocked if they saw his results, but he wasn’t ready yet. It had to be perfect, and he had to prove it could work in humans. The formula was a veritable cocktail of chemicals that affected multiple factors related to growth: altering myostatin, gene expression, pituitary gland functioning, metabolism, mitochondria function. The applications would be stupendous.

If it weren’t for that goddamn Institutional Review Board. Dave sighed to himself as he looked over the stack of IRB paperwork he still had to do. It was the ninth time he had been rejected for human trials, and he was at the end of his rope. How was he ever supposed to make this discovery without human trials? The IRB claimed he should only test the formula on people with muscular dystrophy, and while that was one potential application, the whole point was to see what sort of effect it would have on a healthy individual. He shook his head. Shortsighted fools. He needed to do test this, but knew he would have to defy the IRB to do it. It would cost him everything…but was it worth the risk?

It was all a moot point without the right subject for the test anyway. He needed someone who wouldn’t mind potentially growing bigger, someone with the right genetics to get the most out of the formula so he could prove his point.

He started poking around the college website, looking at the football team schedule. They were D1 and did better than usual this year. It was May now, almost the end of the school year. Surely there would be a student looking to get bigger for next year and make the team. Hmm.

Dave looked back to the IRB paperwork one more time. Fuck. He shoved it into the garbage and opened a blank Word document on his computer and started to make a flyer to hang around campus.

ARE YOU LOOKING TO ADD WEIGHT AND MUSCLE OVER THE OFFSEASON?

SEEKING VOLUNTEERS FOR TRIAL ON NEW SUPPLEMENT, RIGHT HERE ON CAMPUS FOR THE SUMMER.

THIS IS A PAID INTERNSHIP!

PLEASE CONTACT THE EMAIL AT THE BOTTOM FOR MORE DETAILS.

Dave smiled and printed off a couple copies to hang up around the weight room where the football players went to train.


Ryan thumped open the door to the locker room after another lifting session. He was dripping with sweat; his Underarmor shirt was totally soaked through and he was exhausted. It was leg day, so that was always extra intense. He felt good and had hit a new personal best on squats—495lbs, much to his and his teammates delight—but he still felt frustrated. He stepped on the scale in the gym and checked his weight. Still 250. Still. Jesus, he just couldn’t get past that damn number.

It had long been his dream to be on the starting offensive line. He had done community college freshman and sophomore year to take care of some basics and save money, and he transferred this year after getting straight A’s. He was going for a major in microbiology with the eventual goal of doing research or becoming a doctor, but he wanted to make his football dream happen while he could.

The problem was he had a hard time putting on weight. He had always been strong, and in high school that strength allowed to him to play on the line despite being smaller than his teammates. He ate and ate, lifted five times a week and took plenty of protein shakes and pre-workout supplements to give him every edge he could think of without using steroids, but nothing seemed to work.

Dismayed, he wiped the sweat from his forehead and went to his locker to change. As he turned around, he saw a flyer on the wall of the locker room. It was calling for volunteers over the summer in the microbiology lab, seeking students who wanted to potentially add muscle and size. Was this for real? It sounded like bullshit, and Ryan’s natural skepticism rarely steered him wrong, but it seemed so tailor-made for him. A chance to make some connections with his major and maybe give him a leg up on getting bigger over the summer? He didn’t have anything planned for the summer either, nothing lined up as of yet. It seemed perfect. Ryan grabbed the flyer and took it back to his locker, grinning with excitement.

The knock on the door jolted Dave with surprised. The student who had contacted him wasn’t supposed to show up for another half an hour, but he was eager to get started apparently. Dave walked to the door and opened it, revealing a burly but short athletic-looking young man in a loose tanktop and gym shorts. His chest was thick with muscle and black hair, as were his arms. His traps stood out prominently, making his neck look thick. Looking down, his legs were solid and muscular, built from years in the gym and on the gridiron. He had a trimmed chinstrap beard that framed his face, rounded cheeks but with a strong jaw. Dave was impressed and felt his cock impulsively twitch. He had a thing for muscular, thick football players, and Ryan fit the bill.

“You must be Ryan! Welcome to the lab, I’m Dave,” he said while extending his arm for a handshake. He had to reach down just slightly. Dave was tall at 6’3”, but Ryan couldn’t have more than 5’9” in shoes.

“Thanks Dave, I’m just excited for this opportunity,” Ryan said and rubbed his calloused fingers over his fresh high-and-tight.

“Well I’m glad to have you. You look great! Real nice strong base to build off of. You weren’t on the team last year? I’m surprised!” Dave said and led Ryan into the lab.

Ryan’s grin disappeared and he looked a bit frustrated. “Uh, no, not quite, I was a redshirt rookie. The team is really deep and I’m still just 21, so they felt I wasn’t ready yet,” he said, trailing off towards the end and spinning an empty lab chair. “And, you know, I guess this is the reason I’m here… the coaches said I wasn’t big enough. Next year I’m a senior, so this is sort of my last chance.”

Dave turned to face Ryan and leaned against his lab station, pursing his lips in sympathy. “I know that kind of frustration, man, wanting something and working hard at it but being denied. It sucks! But I’m hoping we can help each other achieve mutual goals this summer, bud,” Dave said and patted him reassuringly on his shoulder. What a big, firm shoulder it was, Dave noted excitedly. This kid was the ideal starting size and shape to react best with the formula, or the mouse analogue… adolescent, or right at the end, bigger than average, solid foundation and seemingly good genetics.

“That’s what I’m hoping, Doc… is it okay if I just call you that?” Ryan asked and stretched his right arm, the muscles in his tris and delts bulging with muscle as Dave nodded. “It’s just that, I’ve been working so hard to put on weight for years now. I’ve tried just about every legal means out there. I’m too smart to do roids, I know what those can do to your body and they’re not worth the risk to my health, but Jesus I’ve been stuck at 250 since I was 17,” he said, lifting his arms over his head, revealing thick rounded biceps and hairy, sweaty pits. Dave could smell his pungent funk just slightly.

“Well, I think I can help. You mentioned you were a microbio student, right?” Dave asked. Ryan nodded. “Let me show you what I’ve been working on,” Dave said. Ryan leaned in closer, his bare shoulder brushing against Dave slightly. Dave took a breath to steady himself. He hadn’t thought that his test subject would be so handsome and already so burly. “Um, so, yeah, here’s the basic idea of what I’m going for,” as he started to explain the basics.

Ryan picked up on everything quickly, his passion for the subject and classes he was taking that semester helping him understand things better than Dave expected. “Doc, this is really amazing! I would have never thought to combine some of these effects together. Your animal models are super promising too. I can’t believe the IRB guys are giving you such a hard time. Think of the potential of this!” Ryan said excitedly. He paced around the lab for a moment. “So, uh, when can we get started! I can’t wait to try this stuff out! I just know it’s going to work!”

“Right away! We just need to do the injection once and it’ll have a permanent effect on your body… the proteins that inhibit growth, growth hormone production, metabolism and muscle and bone density, the way your body processes food… everything is going to be changed. Are you sure you want to do this?” Dave asked seriously, walking up to Ryan and making sure he was listening carefully.

Ryan looked back seriously and grabbed Dave by both arms. “Doc, I’ve never been more sure of anything in my life!” Dave was taken aback, as Ryan’s thick fingers and strong hands pressed into Dave’s meager arms, but he grinned. He had his subject

“Alright then, big guy, let’s do some measurements first.” They went back into another room with a scale, measuring equipment, and computers. “Go ahead and strip down to your boxers.”

“Sure thing Doc,” Ryan said as he shifted around and took off his tank top, revealing his thick torso. He definitely had some extra padding on his body, but Dave could see the thick hard muscle bulging out underneath. He had a thick dusting of dark chest hair that was spreading down his belly in a line down the middle. His thick thighs were equally hairy.

When he was done undressing, they went through doing all the measurements: height (5’9”), weight (249lb), body fat percentage, measurements of his chest, upper arms, forearms, waist, thighs, calves, and neck, and so on. Dave had to focus hard while measuring, as he was brushing against Ryan’s thick build constantly.

“Go ahead and flex your right arm, Ryan,” Dave said. He obliged, raising up his thick arm and flexing, the round bulging bicep swelling up bigger.

“Heh, sorry Doc, didn’t have time to shower this morning after the gym,” Ryan said sheepishly as Dave wrapped the tape around his arm.

“It’s all good, you’re a young athlete, it’s to be expected,” Dave said with a grin and tried to control the growing chubby in his pants. “A-anyway, arms are a solid 18 inches around. That’s good! You really have just the perfect starting baseline stats for this experiment. Despite your struggle to put on weight, you actually have a great bone structure and genetic background to put on size. Having a 50-inch chest and 28-inch thighs doesn’t hurt either!” Dave said and patted Ryan’s big round shoulder.

“Thanks Doc, I work really hard at it. So, uh, now can I get that injection?” he asked hopefully.

“Oh yeah, of course,” Dave said and opened a drawer and pulled up a syringe with a golden-looking liquid. He popped the cap and stuck it in Ryan’s meaty arm, plunging it all in.

“Wow, this is so great. I can’t wait! Just…mmmph, man you have no idea!” Ryan said excitedly as he started putting his clothes back on. He shook Dave’s hand vigorously. “So what happens now? Do I need to do anything special? When should we meet up again?”

“Hehe, alright eager beaver, just chill,” Dave said and tensed his sore hand after Ryan’s strong handshake. “It might take a week or two for you to notice any significant changes. Just lift and eat like you have been normally. Come see me in a week. There’s only a couple weeks of school left, so I want you to be focused on your studies still. We’ll ramp this up after finals. Sound good?” Dave asked.

“Yeah Doc, sure thing! Can’t wait until this stuff kicks in. See you soon!” Ryan said and turned to leave, his thick butt looking strong and round in his gym shorts.

Part 2

Dave didn’t hear from Ryan for a week after the initial treatment. Dave wasn’t too concerned about it, since it was end of the year crunch time for finals and stuff after all. After six days he decided to reach out and text the big jock and ask how he was doing.

Dave: Hey there Ryan, just checking in. Feeling any effects of the treatment? Let me know if you can come in sometime in the next couple days

Dave waited a few hours before he heard back. Ryan was probably busy studying for finals, but Dave couldn’t help but be eager to see if his formula was really working on a human. Finally as he was getting ready to leave the lab for the day, his phone buzzed.

Ryan: Sup Doc? Hehe get it? (rabbit emoji)

Dave rolled his eyes a bit and texted back.

Dave: Haha funny. So how are you doing?

Ryan: Holy shit doc this has been a crazy week can’t wait to show u. Been making GAINZ lol (muscle and weight emoji)

Dave grinned and pumped his fist. It was working

Dave: That’s great, Ryan! How are you feeling? Any side effects or discomfort?

Dave didn’t hear from Ryan for a few minutes and packed up and starting leaving for his car. In the parking lot he got another message and he couldn’t help but look right away.

Ryan: Fucking awesome! Super energized and swole all the time. Feeling hungry all the damn time tho haha

Dave: Great! Let’s meet tomorrow in my lab after your classes. How are those going btw?

Ryan: Uh not so great but its all good lol been spending so much time in the gym this week I’m starting to forget stuff I guess

Dave frowned and shook his head. He didn’t want Ryan, a smart kid, to get distracted by being part of the study, but he was glad he had found a subject before most students left for summer break.

Dave: That’s not good! Make sure you finish the year strong, you’ll have all summer to lift.

Ryan: Haha ok doc, it’s just so exciting! See u


Dave had got a text from Ryan half an hour ago that he was heading over from the gym but the kid still wasn’t here. He was starting to wonder if he would actually show up when he heard the door open in the other room.

“Yo Doc! Sorry I’m late. I decided to do one more set of preacher curls and I guess I lost track of time for a sec there, heh,” Ryan said, his voicing sounding a little deeper than Dave remembered when he saw him last week. Hopefully he didn’t have a cold or was feeling a weird side effect from the formula.

Dave got up out of his lab chair and walked over to the door. He opened up, and there was Ryan, looking absolutely huge, significantly bigger than he was a week ago. His white under armor shirt looked grey because it was soaked in sweat, and it looked like it might have been straining Ryan’s movement because it was so tight. The huge jock was wearing flip flops but Dave noticed that they looked too small for his big feet. His arms and delts had become boulders of muscle, his whole body looked thicker and harder than last week. His gym shorts were plastered to his tree trunk legs and beefy ass. His nipples protruded out of the shirt, capping thick pecs that twitched as Ryan turned to the doctor.

Doc! There you are, man. Fuck, what a great week it’s been. Look at the gains I’ve made, dude! This shit must really work!” Ryan said as he bounded over to the skinny doctor and wrapped him in a bear hug. Dave gurgled as Ryan squeezed the air out of him and lifted him up then set him back down.

Dave caught his breath and backed up, taking in the size of his test subject. “Ryan, this is… this is unbelievable! You’ve grown far faster than any of my predictions anticipated!” Dave walked a bit closer and noticed that the junior seemed taller, maybe only a couple inches shorter than his 6’3” rather than being well under six feet. Ryan had also shaped his hair into a short spiked mohawk, the sides of his head showing only stubble.

“Doc, just call me Grunt man, that’s what all the guys on the team are calling me, especially now!” Grunt explained and puffed out his big chest. “I do that a lot when I play and I definitely when I lift! Been hitting PRs on all my lifts all week, it’s unreal! I just keep packing on size. Every morning I wake up and weigh myself and I’m like 5 or 10 pounds bigger, dude.” The muscular jock set his backpack down and took out a shaker bottle filled halfway up with protein powder and went to a sink to fill it up. “The guys on the team said I’ll definitely make the starting offensive line if I keep this up!”

“Rya—Grunt, how much are you weighing now?” Dave asked excitedly.

Grunt shook his protein shake and shrugged his shoulders. His traps bulged up impressively as he did. “Yesterday morning I was 295 but I’m hitting gains so fast I bet I’m bigger. I bet I broke 300 today! Fuck, I thought it would take all summer to get up to that!” he said and proceeded to chug the entire thick shake.

Dave reeled at this information. Never in any of his trials did his mice subjects grow this fast. Rya—Grunt was packing on at least 2% of his body weight in new mass every day, and if anything it seemed to be accelerating.

“Grunt, this is incredible, but I wond—” Dave started by was cut off by Grunt’s explosively loud burp.

“Hehe, sorry Doc,” Grunt grunted and burped a bit more. “Just can’t seem to get enough food these days, I’m always hungry! Got anything else around here I can eat?” he asked and started opening random cabinets even though they were all labeled with lab different types of equipment.

Dave started towards him but then pulled himself back. “Uh, that’s… not in here, but I can give you a couple of the protein bars I keep in my office,” Dave said. Grunt’s eyes lit up and he rumbled past Dave, his wide delts brushing past the skinny doctor and into the office.

“Grunt, uh, how else are you feeling?” Dave asked as the big football player thrust his hand into the box of energy bars and came away with three of them.

“Amazing!! I’m like never tired, I could just keep lifting and lifting lately it seems. I sleep really well, but man when I want to I just have stamina to go as long as I want. I could have totally kept lifting just now but then I remembered our meeting. I almost forgot, I was in such a zone,” he said between a mouthful of chocolate protein bar. “Check this out, Doc,” he said and lifted up a big arm and flexed dramatically. “Boom!”

Dave’s mouth dropped open, preventing him from speaking for a moment. The huge bicep peak rose up impressively, round and hard, thick and massive. It had to be 20 inches around now. The kid was still slick and shiny with sweat covering his arms and shoulders, which added to their impressiveness. Dave reached out and touched the arm, rubbing around its circumference, feeling the hard mass undulating.

“Yeah I got ‘em really pumped for you man, pretty sweet huh?” Grunt boasted as he put his arm down and took a breath, swelling his pecs up and out. “Chest is up to 56 inches too. I’m almost the size of the biggest guys on the team now! I’m gonna meet with coach tomorrow and show him my progress, I bet I’ll be big enough to make the team now! And we’re just getting started, huh?”

Dave backed up and took a deep breath, trying to control his shock and excitement. “Th-that’s right big guy! And yeah, I bet your coach will be blown away.”

Dave looked closely at Grunt’s hulking physique. He was way bigger already, all over the place, even a little taller. It was truly alarming, but he couldn’t help but be elated. The formula was working, better than he ever expected. He might have to find a way to stop it if this pace of growth kept, but for now he was pleased.

Grunt turned around and grabbed another protein bar, showing his wide back to Dave. His lats were thick and wide, his traps bulging up towards his neck. Dave couldn’t help but reaching forward and squeezing his huge delts and lats, admiring their thickness.

“Jeez, wow Grunt, this is, really, um, impressive!” Dave said nervously as he rubbed his hands up and down the big jock’s back. He removed a hand to adjust himself and then moved his hand down to pat Grunt’s round ass.

Grunt turned around and grinned awkwardly. “Uh, thanks Doc, no homo though haha,” he chuckled nervously and gave Dave a friendly punch to the shoulder. Dave shifted his weight back a bit in response and blushed in embarrassment. Of course he wasn’t gay, Dave thought to himself. He felt bad for even letting himself hope that.

“Haha, yeah for sure man, sorry. I’m just excited for your, uh, gains! Hey, let’s weigh you before I let you go,” he suggested, changing the subject. He asked Grunt to step up on the scale. It clattered and groaned as his big feet got on. After a moment it finally evened out at 306.

Wow, told you I blew past 300! Fuck yeah!” Grunt boomed and held up a hand to high-five Dave. Dave obliged and Grunt slapped his hand hard, making it sting.

“I just wonder how this is all happening so fast, big guy,” Dave said seriously, trying to engage the young hulk’s mind. “In the animal models, the mitochondria couldn’t produce ATP efficiently enough to handle so much growth at once, and there was a limit to how much food they could process efficiently. I wonder what might be different with you. What do you think?” Dave asked and then looked expectantly at his summer research student.

“Uh, man, that’s a good question Doc, uh, I’m not really sure though…” Grunt trailed off and leaned his scruffy cheek against his big right fist. “I’m trying to remember…what, uh, what does mitochrondria do again?”

Dave was taken aback by the question—that was basic biology, as mitochondria were one of the most important organelles in every cell in the body—but he explained. “Do you think maybe the gene expression modifiers in the formula are maybe effecting the transcription differently? Or maybe your pituitary gland is just responding extra well to the hypothalamic stimulants?”

Grunt’s eyes got a glazed over look as Dave talked and his mouth started to hang open. “Uh, wow, that all went over my head Doc, sorry. Looks like we’ve got some questions to think about though, huh? I gotta get going though, gotta get back to the gym! I told one of my lineman buddies that I’d lift with him before dinner.” He got up out of his chair—man he really was getting taller—and grabbed the last few protein bars from Dave’s drawer and shoved them in his backpack. “We’re doing chest and tris! I did back and bis this morning for three hours, so I’m ready to go!”

“Wait, Grunt, don’t neglect your finals! I know you’ve got good grades so far, but I’m worried you’re letting this growth spurt go to your head. Just, focus on your classes this week, ok?” Dave asked before he could take off.

Grunt grinned at Dave. “Sure thing Doc, can’t wait to meet up again. So, uh, next weekend after finals?”

It was like he hadn’t even listened to… “Yeah, let’s touch base on Friday after finals to talk about our plans for the summer,” Dave said.

Grunt was already walking out of the room as Dave was talking. “Ok, see you then Doc, gonna go lift more! Gotta stay pumped! Thanks for everything, Doc!” the big jock said and then left.

Dave took a deep breath and sighed. This was going to be a crazy summer. He was excited, but was worried about that last exchange. How could Ryan—Grunt—not know what mitochondria does if he’s such a smart biology student? He also totally zoned out the questions about what might be causing the growth and started talking about the gym instead. That wasn’t like him. Dave pursed his lips, went back to his office, and threw away the empty box of protein bars.

Part 3

Friday rolled around and Dave had worked all week thinking of why Grunt was growing so fast, but hadn’t found anything. He had been busy with finals, of course, and was glad the school year was finally over so he could focus on his research.

While he was still elated that his formula was working so well, he was dealing with the repercussions of Grunt growing so fast. Dave had heard some interesting rumors around campus about Grunt. On one hand, the coaching staff and football players and fans around campus seemed delighted by the growth spurt of the newly huge lineman, chalking it up to hormones, a late growth spurt, and the payoff of years of hard work at the gym and on the gridiron. His professors, however, were less happy. They seemed to lament the loss of one of their most promising, inquisitive, and charismatic students. His biochemistry professor had even emailed, asking Dave if he knew anything about his star student turning into a gym-obsessed meathead who had skipped class the last week and a half of the semester and who flunked the final.

Despite his concerns about the side effects, which seemed to be clouding Grunt’s focus at least, if not his intelligence, Dave felt he had to press on. It was the culmination of years of work, and he wasn’t going to let anything stop him, especially not when his subject seemed to enjoying the effects so wholeheartedly.

On that note, Dave heard Grunt’s heavy footsteps coming down the hall. He entered the lab, and once again Dave was astonished. Grunt had grown even more, to a shocking extent. The lineman was now easily the biggest student Dave had ever seen on campus. His shoulders spread nearly as wide as the doorframe, and he was a bit taller than Dave now. His arms stuck out to the sides, his triceps and lats pressing against each other. Grunt wore a thin tank top and basketball shorts. The sides of his pecs were marked by a series of red stretch marks underneath a forest of dark chest hair that looked to be spreading farther than Dave remembered. His belly was growing too, fueled by the massive amount of food Grunt had been eating, and stuck out an inch or two past the limits of the shirt. He stood with his legs spaced far apart, his stance wide to necessitate the space required by his massive thighs. He wore new-looking sandals, which already seemed too small on his thick feet. He was once again covered in sweat, fresh from the gym, and he had a big puppy-dog grin on his face.

Doc! Great to see you, bud!” he bellowed and slapped Dave on the shoulder. Dave lost his balance and fell into one of the lab tables, nearly falling. “Heh, oops, my bad, still getting used to my new size and strength! People seem so much smaller all of a sudden!” Grunt said and scratched the edge of his hairy chest, his bicep bulging as he did.

“I-it’s alright Grunt, it’s good to see you too. Wow, you’ve just kept on growing, huh?” Dave asked, offering him a protein bar. The big jock took it automatically and started eating. He wasn’t in the habit of turning down any kind of food these days, it seemed.

“Yeah, I guess so, huh?” Grunt asked dully as he chewed. “Been lifting a lot and trying to get as big as possible! I love lifting, man, it’s the best,” he said and popped the rest of the bar into his maw. He looked like he hadn’t shaved in several days and was very scruffy.

Dave couldn’t help but grin at Grunt’s enthusiasm, but he also had to ask him a more serious question. “That’s great man, but I heard you kind of struggled on your microbiology finals? Greg told me you flunked it and only ended up with a B minus in the class after having an A all semester?” Dave asked, raising an eyebrow.

Grunt rubbed his beard scruff and squinted his eyes, thinking. “Oh yeah, my science class, yeah that was tough! Guess I should have studied more, huh? I didn’t do so great on the rest of my finals either, but it’s been hard to think lately. Maybe because my clothes are getting so tight? This is like the only shirt that fits me anymore,” he said and rotated his torso a bit, showing me the loose-fitting tank top. In the process of doing so, his stomach grumbled audibly.

Grunt stepped closer and looked behind Dave’s back to the lab table. “Got any more of those, Doc? I can always use more protein!” he said as he looked. He smelled foul, like he hadn’t showered in days. Dave noticed how dirty his tank top looked. His basketball shorts were the same ones he had worn last week, only obviously tighter. There were stains on them, from food or something else he couldn’t tell.

“Grunt, uh, when was the last time you did laundry, bud?” Dave asked as he shifted away from the big guy and grabbed his notes.

“Oh yeah, laundry, I knew I was forgetting something…” he said absentmindedly. “I have a load still in the laundry room at my building that I left there… jeez… when was that?” he said and drifted away, his eyes becoming blank as he struggled to remember. “Oh well, I can get those later. Yeah, I guess I should, but I’ve been so focused on the gym and stuff, you know. Forgot to shower the last couple days, hehe, sorry Doc,” he said and lifted his huge arm. It had to be 22” around by now. He turned his head into his hairy sweaty armpit and sniffed deeply. “Woooo, man, yeah that’s my bad,” he said and sniffed again.

“Yeah, you really need to man,” he said, letting out a cough. “It’s pretty bad,” He backed up a little. “Now, let me get down to business since I still have some grading and stuff to finish up. So, this summer!” he said, touching Grunt’s bicep to get his full attention.

Grunt grunted and grinned. Dave figured him to be 6’4” and somewhere around 350 pounds at least. He folded his arms, which made his arms, chest, and shoulders seem even bigger.

“Uh, the plan for you is, uh, they’ve got some summer on-campus housing for you to live in. You’ll have your own single room, which I already have keys and an information pack for right here,” Dave said as he handed Grunt a manila envelope. “We’ll meet here every morning to check on your progress and measure any changes to your body, your mental state, your health, and so on. Occasionally I’ll have some tests or activities I’ll have you do, but most of the time you’ll have a lot of free time to do whatever you like during the day!” Dave said enthusiastically. “Everybody likes free time, right?”

“That sounds great Doc, more time for the gym!” Grunt said pleasantly, smiling at the possibility of being at the gym for as long as he wanted.

“That’s right, but don’t overdo it. You should just keep to your normal routines before you had the injection, you know, play some games, watch some movies, whatever you want,” Dave said, but Grunt didn’t even look like he was listening.

“Uh, alright big guy, well I’m gonna let you go find your new room so you can move your stuff over there, ok?” Dave asked as he waved his hand to Grunt to get his attention again.

Grunt shook his head a little, like he was trying to focus through the clouds. “Oh, yeah, sure Doc that sounds good! I’m excited! I’ll see you on Monday then I guess,” he said.


The rest of the month fell into a familiar pattern. Grunt would wake up early and get to the school gym as soon as they opened. After a few hours, a timer that Dave had set would go off and he knew it was time to go to the lab. Dave would meet him there, be impressed by Grunt’s noticeable gains, and take measurements. Each day, Grunt’s measurements would be slightly bigger than the last: a few pounds heavier, chest and arms and legs all thicker with more fat and muscle, head a little taller. Sometimes they would do some tests, like grip or strength tests, or Dave would take blood or tissue samples. Grunt was in exceptional physical health. He had got a cold right after finals but he seemed totally healthy again in a day. Dave took a tissue sample, which normally would take a couple weeks to full heal, and any trace of it was gone in two days. After that, Grunt would go have lunch at the cafeteria, staying there for over an hour at a time to continuously eat and eat. After that, he would take an afternoon nap, then get up around 3 to lift. Then dinner. Then back to the weight room. Then back to his dorm where he would sleep for 9 or 10 hours at a time.

All the while, Grunt seemed to be constantly happy and excited, eager to add on more size and help Dave with his research however he could. The mindless routine of the research seemed to suit him well.

Dave quickly realized that most of the funding for the experiment would have to come from himself since he never received a grant from the government, and it would be more expensive than he thought. Grunt had outgrown all of his clothes, sometimes shirts or shorts tearing right there in the lab at Grunt showed off his latest developments. He liked flexing for Dave and showing how big he was getting. It filled him with pride that Dave was so pleased, and increasingly he hoped to make Dave happy whenever he could. Dave bought him new clothes whenever he needed, but it was getting harder to find stuff that fit and wasn’t expensive. The amount he was spending on protein powder was a whole other matter, but Grunt said he needed it.

Of course, it had been really difficult for Dave to keep his hands off the enormous football player. His lust for the big man increased day by day as he grew and grew. It was especially tough when he measured Grunt’s thick thighs, as it required Dave to get on his knees in front of the behemoth. Last time he did that he accidentally brushed against the tremendous bulge in Grunt’s thin basketball shorts. Grunt didn’t react except to make a guttural sound and adjust himself as he chubbed up. Dave just gulped and stared at what appeared to be a massive thick snake growing thicker and longer and quickly finished measuring Grunt’s thighs.

Not everyone was so pleased by Grunt staying on campus over the summer, or by his freakishly growing body. By now everybody who worked down at the gym knew him, perhaps all too well. At first they had been happy for him and his shocking progress, cheering his gains and encouraging him, but now he was getting to be overwhelming. Grunt had maxed out or was pushing the limits of many of the apparatus at the gym and was scaring away other students, or so said the email Dave had got from the head of the gym for their summer programs. Grunt’s sweaty funk would stink up whatever area of the gym he was in, to the point where students were complaining. Dave reminded Grunt to take care of himself, to shower and do laundry, but Grunt said he had a hard time remembering.

One thing he didn’t have trouble remembering to do was eat. Dave had also gotten complaints from the cafeteria staff, about the giant football jock who would come in alone and stay for hours at a time, stacking his tray with food, then coming back for more every 15 minutes or so. The staff said he would often cut in line or accidentally push people out of the way to get more food along with the usual complaints about his hygiene. And of course, the sheet amount of food he was eating wasn’t something they had planned for. Sometimes he would take so much that others behind him in line would have to wait for more to be cooked up. Grunt didn’t seem to notice or care unless someone said something, but most were too afraid to talk to the juggernaut.

All the while, Grunt grew and grew each day, swelling up with more strength, more height, more muscle, more fat, more raw size, growing heavier and thicker and wider. By the end of the month, he was a 7’ tall and 600-pound monster, more than double his weight a month ago.

He came in to the lab on Tuesday after Memorial Day, and Dave had some big changes in mind. The beakers in the cabinets of the lab rattled ominously as Grunt approached. He bumped open the door, and bent down a bit to see Dave through the door. He grinned and chuckled and then twisted and bent over more to squeeze through. The Underarmor shirt Dave had given him a few days ago was already skin tight. His hair was freshly cut into a spiky mohawk, which had become part of his signature look, and at least he had showered this time. He stood back up to his full height and towered over Dave, 9 inches taller and triple the weight. He planted himself and grinned down at Dave expectantly.

“Whoa, what’s with the ink big guy? When did you get those?” Dave asked and pointed to Grunt’s arms. Since Dave last saw him on Friday, he had got a couple prominent tattoos. Along the tricep of his right arm, it said BIGGER in ornate capital letters. He twisted around to show Dave his other arm, which said STRONGER in the same text.

“I was hanging with some football buds over the weekend and they told me to get tattoos. They look cool! I got a big one on my back too!” Grunt boomed excitedly. His voice had grown deeper and louder, and he didn’t seem to have much self-awareness of how much his voice carried anymore. He reached down and took off his shirt, tossing it onto the ground. It spread out like a tarp on the floor and he turned around.

Along the top of his insanely wide, muscular back across the traps and rear delts, it said MONSTER.

“Pretty sweet, huh Doc? Because I’m a huge muscle monster and I keep growing bigger and stronger!” he said while flexing his huge triceps. He then lifted his arms into a massive double bicep flex, the muscles on his back, shoulders, neck, and biceps erupting with size. Lumps and bulges of muscle spread out twice as wide as Dave’s shoulders, dancing and twitching as he flexed.

Grunt turned around and looked down at Dave, shirtless now, his huge pecs heaving as he breathed heavily. “Well Doc, what do you think?” he asked.

“Uh, wow man, those look awesome! They look all healed up already. Those must have taken a long time to do!” Dave said and went around to Grunt’s side to get a closer look at the BIGGER tattoo. It was shiny and new, black and clean. It was totally healed up even though he had only got it this weekend. Dave ran his hand over the tattoo, feeling the hard mass underneath the tight skin. Grunt flexed and the massive tricep bulged out even bigger and harder.

“Sure did! Felt like I was sitting there forever, heh, but the tattoo guy was nice. He liked my muscles, I think!” Grunt beamed proudly and leaned down and flexed his bicep for Dave, causing the BIGGER tattoo to dance and shift. “He kept rubbing my arms and asking me to flex. I liked it!”

Dave suddenly realized how much these must have cost. “Grunt, how did you afford these?” he asked, concerned.

“Oh I just used some of my college loan money, it’s ok,” he said and twisted his thick neck around to appraise the peak of his bicep. It was thick and round, the peak rising high and with a throbbing vein on it.

“Uh, oh, that’s...well, that’s great then,” Dave said, not wanting to tell him how terrible of a decision that was. He shook his head and decided to get on with today’s work.

“Grunt, today we’re not gonna do any measurements and tests. Today is special!” Dave said simply. He had learned over the last two weeks if he tried to complicate things too much, Grunt would just look confused or nod his head without saying anything.

“What are we gonna do today, Doc?” he asked and scratched his balls, the weighty package flopping around in his hand. He was becoming less inhibited about touching himself, especially around Dave.

“Grunt, you’re getting too big for the dorms, and I’m getting some…comments from people around campus about your behavior in the gym and cafeteria and stuff,” Dave said cautiously, not wanting to anger him.

Grunt looked embarrassed and his clean-shaven face grew red. “Sorry Doc, I just get real hungry and I like to lift a lot of weights,” he said earnestly. “You’re not mad at me, are ya?” he asked and looked down at me over his barrel chest. He idly scratched the dense dark fur on his right pec, flicking over the thick meaty nipple.

“Of course not, big guy, if anything this just means the experiment is going even better than I expected. You’re getting so big, normal people can’t handle it!” Dave said and patted him reassuringly on the shoulder, feeling the dense pack of muscles on his arm. Grunt grinned, reassured. “So here’s what I propose we do,” Dave pressed on. “Why don’t you come live with me at my house for the rest of the summer? We can keep doing our research there,” Dave said hopefully.

Grunt looked confused for a minute, considering what this might mean, but then his look of confusion turned slowly into a toothy grin. “Really Doc? I get to live with you?” he asked excitedly as he grabbed Dave’s arms in his enormous meat-paws.

Dave froze up a bit as Grunt grabbed him, the big hands wrapping all the way around his arms. “Y-yeah big guy, I’m already getting a home gym installed in the garage, which will be your own space. This way you won’t have to worry about forgetting stuff either, because I’ll be there to take care of you. Sound good?” Dave asked.

Grunt lifted Dave up as he straightened out, the top spikes of his Mohawk almost scraping the ceiling. “Doc that sounds amazing!! I can’t wait! We can eat together, and I can lift all day in the garage! I hope you got heavy weights, Doc, the school ones are getting too light!” he bragged and squeezed Dave in his hands, compressing Dave’s arms and making him wince in pain. Grunt then shook Dave up and down and accidentally bumped his head against the ceiling.

“Grunt, put me down!” Dave said and Grunt quickly obeyed, setting Dave down and then standing back up to his full height, looking down at Dave expectantly. That was weird. “Uh, yeah, that’s the plan big guy!” Dave said and backed up a little. “I was actually hoping you could help me get that going today. Sound good?” he asked tentatively.

Grunt nodded vigorously. “Of course Doc! Oh boy, I’m gonna be your roommate!” he said and in his excitement grabbed Dave again and put him in a headlock. His strong, solid bicep smooshed against the side of Dave’s face, wedging him against his pec. Grunt’s nipple poked into my cheek. Grunt just laughed and shook Dave around a bit. It was the best way to continue with the experiment, but Dave couldn’t help wondering if he’d bitten off more than he could chew.

Part 4

Dave turned over in his bed and looked at the clock. 3 a.m. and he still couldn’t sleep. He sighed, but the sound was drowned out by the sound of Grunt’s snores from downstairs. Dave had converted the living room of his house into Grunt’s bedroom; it was the only place in the house big enough for two king-sized beds set up next to each other. It was more than big enough for him now, but Dave knew Grunt would need as much size as he could get sooner than later. What Dave hadn’t counted on was how loudly the big man would snore. The sound of it filled the entire house and seemed to rattle the windows with its depth and volume.

Flopping back over onto his side, he put a pillow over his head and hugged his head, trying to block out the noise. He resolved to go to the store tomorrow and get some heavy-duty earplugs as he finally succumbed to sleep.


Dave groggily opened his eyes as he sensed the lighting in his room change a little. He shifted to the side and suddenly saw a man standing in his bedroom, a massive mountain of thick muscle and furry belly blocking the light from the window. Dave gasped and sat up in his bed, shocked.

“Whhaaaaaaa, what the fuck,” Dave yelped and looked up at the stranger in his room, only to realize it was Grunt standing next to his bed, looking down at him.

“Mornin’ Doc!” Grunt said with a grin.

“Ryan, man you can’t just do that, you scared the crap out of me,” Dave said sleepily as he rubbed his face. He looked at the clock. 7 a.m. He had only got four or so hours of sleep.

“Ryan?” the massive football player asked, confused. He rubbed his chin, bicep bulging as his arm moved, and then his eyes lit up and he looked back down at Dave. “You mean Grunt, Doc. I don’t really go by Ryan anymore, hehe,” he said as he loomed over the bed. Dave suddenly felt very vulnerable laying in bed wearing just his pajamas with a 7-foot monster standing over him. “Just call me Grunt!”

“Uh, right, sorry bud. So what’s up?” Dave asked sleepily. “I’m not used to having anybody wake me up, much less a guy your size!”

Grunt sat on the edge of the bed, the mattress and frame creaking to the point where Dave became concerned. All he was wearing was a tight pair of boxer briefs. It left little to the imagination and hugged his ass and thighs tightly, muscles straining the threads. His naked torso was thickly muscled.

“I’m ready to get my day started but I wasn’t sure what I should do first, so I came to see you. Also I’m real hungry and I’m not sure what I should eat. What do you think?” he asked earnestly, leaning against Dave a little and looking very intent.

Dave looked up at the massive 21-year-old jock with wonder. His mental degradation had gone further than he had expected, and Grunt now seemed totally incapable of thinking for himself. Grunt waited patiently for instructions.

“Uh, well, I can go ahead and get up and make you some breakfast, but you’re welcome to anything in the kitchen,” Dave said patted Grunt on his side, feeling the swollen lats. His skin was warm to the touch. Grunt leaned into Dave some more.

“Anything I want? Really?” Grunt said excitedly. Dave noticed that the bulging in Grunt’s boxers was growing steadily.

“Yup, now that you’re living here, what’s mine is yours. I’ll meet you downstairs in a bit, ok big guy?” Dave said. He decided to be bold and shift his hand up from Grunt’s lat onto his chest, rubbing the thick, furry pec. Dave couldn’t believe how heavy and firm it felt. He looked up at Grunt, expecting to see disapproval, but Grunt didn’t seem to mind the hand on his chest at all. Quite a difference than a few weeks ago.

Grunt smiled and Dave heard his big tummy rumble. He shifted his weight and stood up again, towering over Dave. The bulge in his boxers tented out obscenely, pointing right at Dave.

“All right Doc, thanks! I’m gonna go get started on breakfast, I’m starving! See you downstairs!” he said enthusiastically and walked out the room. His heavy body made the entire house shake when he walked. He bent down and shifted sideways to get through the doorway and headed downstairs; Dave could hear the steps groaning in protest of having to handle 600 pounds of football jock beef.

By the time Dave got downstairs, the half-naked Grunt was already shoveling big spoonfuls of yogurt into his mouth and had polished off half a gallon of milk. Dave set about making scrambled eggs and toast and bacon while Grunt kept eating. He ate like a starving man, eating as much and as fast as possible, breathing heavily and pausing only to grab the gallon of milk and take big swigs to wash everything down. He moved on to the bags of granola from Costco and a bunch of bananas and peanut butter once the yogurt was gone.

“So, ‘Grunt’,” Dave said awkwardly, trying to make conversation. He still wasn’t used to having a behemoth jock living and eating with him. “Did you sleep okay last night?”

“Great!” he mumbled through a mouthful of food. “Those king-sized beds really do the trick! I had outgrown my bed in my dorm room weeks ago. I could really stretch all my muscles out last night!” he said and demonstrated, lifting his arms into the air and stretching his massive frame, every muscle on his torso bulging and flexing.

Dave almost dropped the spatula as he stirred the dozen eggs he was making. The thing that kept blowing him away about Grunt’s size was how he still looked so full and thick even though he was getting freakishly tall. Usually guys his height looked lanky, thin, and long, but Grunt still had the thickness and girth of a powerlifter.

“T-that’s great, big guy,” he said while stirring the eggs. “You sure were loud last night though, I think I might have to get some ear plugs because of your snoring,” Dave said while pulling the bacon out of the oven and putting it onto paper towels. As he shifted the eggs onto a big plate, Dave suddenly felt something hard and warm press against him from behind.

“Sorry Doc… say, are those done?” Grunt growled into Dave’s ear right behind him, leaning into him more. “I’m still so hungry,” Grunt rumbled. The heat and hardness of his torso pressed against Dave’s back, and he felt Grunt’s enormous thick cock poking against his back. Grunt’s huge arms reached over Dave’s shoulders and down, grabbing the plate of food. Grunt’s arms were so much thicker and longer than Dave’s; the researcher suddenly felt very small. “Need more protein to grow bigger,” Grunt said and grabbed up a handful of bacon strips.

He backed away and stepped back to his chair, the kitchen rumbling from the weight of his steps. The chair groaned as he sat down. Grunt dug into the mound of scrambled eggs in front of him. His big traps bulged as he leaned over and ate fast. His square jaw clenched as he chewed. He made snuffing, grunting sounds as he stuffed food into his mouth as fast as possible.

Dave just watched, stunned, as Grunt ate everything. He came around next to Grunt, watching him eat. He stood behind him and grabbed his thick traps. Dave squeezed, and Grunt growled softly and took a deep breath. “Feels good, Doc,” he said and kept eating. Dave pushed his fingers in harder, massaging the enormous muscle. It was so hard, it was nearly impossible for Dave to really massage deeply, but he tried. Dave marveled at the size and density of the muscle, by how hot it felt to the touch, how it twitched and shifted as Grunt ate. He moved his hands over to the bulbous deltoids. His hands seemed so tiny in comparison to the huge round muscle; they were like bowling balls attached to his arms.

Grunt sighed again and set his fork down as he finished all of the eggs, snorting out through his nose. Dave decided to be bold. “Hey Grunt, does this feel good?” he asked as he rubbed his shoulders and moved his hands up to Grunt’s thick neck.

“Mmmmm, yeah it does Doc, keep doing that,” he purred and spread his back wider, the lats and shoulders expanding. Dave gasped as the muscles danced under his hands, causing the huge MONSTER tattoo that spread across his traps to shift. He dug underneath Grunt’s shoulder blades but they were hard as rock. There was a slight dusting of back hair sprouting on the big man’s shoulders and upper back.

“Grunt, can I… feel how big your arms have gotten?” Dave said, gulping and being sure not to lean against the back of Grunt’s chair for fear of him feeling Dave’s hard boner.

“Sure, Doc,” Grunt said happily and slowly lifted his right arm up into a bicep flex. The peak exploded into hard roundness. Dave didn’t quite know where to look; the bicep, the huge round deltoid, the BIGGER tattoo that seemed to stretch awkwardly when the muscle flexed, the enormous traps merging with his neck, all flexing hard, looking like a mountain range of muscle. “I love flexing my biceps,” Grunt said and raised his left arm to flex too.

“I’m gonna have to measure these by hand soon… maybe later today after you lift,” Dave said breathlessly.

“Yeah Doc, that would be fun,” Grunt said proudly. He liked showing off his muscles to Dave. His cock twitched in his boxers, the wet spot down there expanded.

Grunt pushed his chair back and stood up slowly, feeling the fullness of his size. He turned around and looked down at Dave and brought his fists together, flexing his chest and traps and shoulders. “Thanks for breakfast, Doc, I feel so ready to lift now!”

Dave backed up and his mouth dropped open seeing the monster flex up close. “Y-yeah Grunt, it’s out in the garage. Let me show you!” Dave said, trying to regain some of his composure.

Part 5

Grunt had been like a kid in a candy store when Dave showed him the gym setup. Dave had spent the majority of his savings on transforming his garage into a high-quality gym setup. He had bought copious amounts of weights, a heavy-duty squat rack taller and bigger than any he had seen at his gym, a full set of dumbbells that went up to 250, weight benches, pulldown machines, you name it. Grunt was so excited to see it all he had lifted Dave into a massive bear hug, squeezing so hard Dave was afraid he was going to break a rib. Dave said that he had to go to work and told Grunt to lift as much as he wanted that day. He also told Grunt to help himself to whatever he found in the kitchen, especially the tubs of protein powder. Grunt was already bench pressing hundreds of pounds when Dave pulled out of the driveway and left.

That was this morning, eight hours ago. Dave pulled up to his house and opened the garage door. Sunlight flooded into the garage as the door opened slowly, revealing a hulking beast standing in front of the large mirror on the wall, slowly and deliberately doing hammer curls with 200lb dumbbells. He was shirtless and glistened with sweat as the light reached him, massive upper body covered in dark hair, curly and wet from the sweat, swollen with muscle. He lifted the huge weight, his bicep exploding with muscle, thick vein pulsing to feed the growing mound.

Grunt looked up as he saw the door open but didn’t stop lifting. He moved with a steady mechanical rhythm and had perfect form. He looked fresh, like he wasn’t tired at all, even though Dave suspected he had been lifting all day. Grunt bared his teeth, half smile, half grimace from the pain of lifting, and exhaled, blowing a drop of sweat from his nose onto the puddle at his feet as he squeezed out another rep, the heavy weight brushing against his belly as he brought it down, then bumping up against his barrel chest when he brought up back up.

Dave got out of his car and walked into the garage. The entire space smelled like a football locker room, musky and humid and ripe, after just one day of Grunt being in there. He walked up to Grunt, who kept lifting, squeezing his biceps as they bulged harder and stronger.

“Hey bud, you look bigger than ever,” Dave said as he walked up to Grunt. Grunt panted and smiled, looking down at Dave over his pecs.

“Thanks Doc, *grunt* been lifting *grunt* all day! Your gym *grunt* is awesome!” he said and finally bent over to put the weights down. They clunked onto the concrete floor. He stood back up to his full height, towering over Dave. His warm breath smelled like chocolate protein powder. He lifted his arms and stretched his biceps; he reeked of jock BO.

“Nice, glad it fits your needs! Come help me bring in these groceries,” Dave said and Grunt followed behind him without question. It only took two trips despite Dave having several bags worth of food with Grunt’s help.

In the kitchen, Grunt seemed even bigger, his shirtless form stretching close to the ceiling and filling up the space with his thick body. His stomach gurgled and he reached for the protein powder, dumping several scoops worth into the dirty blender. He had clearly already used it several times that day.

“So big guy, how was your day?” Dave asked as he put away groceries.

Grunt finished blending his shake and turned to Dave with the blender pitcher in his hand. The shake filled it to the brim and looked ridiculously thick. “Great! I’ve never had such a good pump, I feel so huge! I lifted all day. Well, I stopped for food a few times. I bet I’ll make the football team now, at my size!” he said and started chugging his shake.

“Oh for sure big guy, for sure,” Dave nodded and realized Grunt had no idea he was probably too big for football now. “Didn’t you get tired or anything?” Dave asked, wondering if Grunt had really lifted for eight straight hours.

Grunt finished the shake and slammed it back down on the counter. “Nope, I don’t really get tired anymore when I lift,” he said and chuckled, the bassy rumble of his laugh bouncing off the ceiling. “I just feel so good, Doc, feel so much power when I lift,” he said and stretched his arms. They bumped into the ceiling. His armpits were wet with sweat. “I could keep going all day, and I don’t really need recovery time now,” he said and he flexed his huge biceps.

“Well bud, go ahead and keep lifting then, I’m gonna make dinner,” Dave said as he stepped closer to Grunt and reached up to feel his immense bicep peak. Dave moved his hand to Grunt’s shoulder. His deltoid felt like a basketball made out of rock. His hand came away covered with sweat.

“Yeah Doc, I’m gonna go lift some more!” Grunt said with childlike excitement and went back out to the garage, ducking his head to fit through the doorway.

Dave wiped the sweat off his hand and set about making dinner. He started looking through his cabinets and the fridge and realized nearly all the food in the house was gone already. Grunt had literally ate most of the food in his house in just one day.

Dave shook his head but also grinned. He couldn’t believe the success of his formula. He never allowed himself to think it would work so well in humans. The intelligence drop side effect was unfortunate but he could work on that. For now he wanted to see how far he could take this. Grunt was the perfect subject and was just as driven to get big as Dave was to see him grow bigger. He could hear the big lug out in the garage, grunting and growling as he lifted, punctuated occasionally by the sound of huge weights slamming onto the ground.

An hour later Dave had baked two pans of beef lasagna, garlic bread, salad, and dessert. He told Grunt to come in to eat, and Grunt bounded into the house like an excited Labrador retriever. He sat right down, dripping sweat on the floor and the table, and dug into one of the pans of lasagna. Like that morning, he ate like a starving man, devouring pounds and pounds of pasta, bread, and salad at an alarming speed.

Dave looked across the table and felt strange. Grunt’s massive proportions made everything else in the room seem weirdly small. Grunt’s fork looked like something for a child’s tea party in his hand. His shoulders were so broad, Dave couldn’t see anything on the wall behind him. Grunt grunted and snorted out of his nose as he ate, occasionally burping and chugging more milk. Dave could almost see him swelling bigger as he fueled his massive body with more food.

Dave finished his first plate as Grunt finished the first pan of lasagna. Grunt looked up expectantly at Dave, wondering what to do next, his eyebrows raised.

“You can have the other pan of lasagna, big guy, go for it,” Dave said with a smirk, marveling that Grunt waited for permission. He was becoming more and more obedient and docile, more dependent on Dave to make decisions for him.

“Oh boy!” Grunt roared and stood up, pushing his chair back and taking two steps over to the stove to grab the other pan. He came back with the whole thing and dug in, shoveling pasta and meat and sauce and cheese into his mouth as fast as he could.

When the meal was over, Dave dumped everything into the sink. Grunt stood up, took a deep breath, and let out the loudest, deepest belch Dave had ever heard. He couldn’t help but laugh at the behemoth, and Grunt grinned, pleased he could make Doc laugh. He rubbed his full tummy, feeling the roundness and weight of it. Grunt was glad his belly was growing along with his muscles. He needed all that girth to be a good offensive lineman and he wanted to make coach and Doc proud.

“Wow that was a good one, big guy,” Dave said and moved closer to Grunt, who was still shirtless. “How are you feeling?” he asked.

“Good! Full! Strong!” Grunt said and looked down over his hairy pecs at Doc. “Jeez, you look small, Doc!” Grunt boomed and he reached forward and gripped Dave’s skinny arms in his think fingers, feeling how much smaller he was.

Dave tentatively moved a hand up and ran it through Grunt’s chest hair, feeling the heat and hardness of his pecs. “Well, that’s because you’re such a big guy, Grunt,” Dave said. “Hey, you should go lay down so your food can digest,” Dave said.

“Yeah Doc, good idea! Always so smart,” the big lug said as he turned and went into the living room. The mattresses creaked as his prodigious mass laid down, and he spread out over the bed.

Dave stood next to the bed, marveling at the enormous physical specimen in his house. He was perfect, and growing bigger and stronger and more muscular by the day. Dave climbed onto the bed and kneeled next to Grunt. The football player didn’t seem to mind at all.

“Hey big guy, I’m going to rub your muscles, okay? I bet they’re really sore from lifting today, huh?” Dave said as he moved closer.

“Yeah Doc, they are,” Grunt said and turned over on to his stomach, showing the wide lats and thick traps. His bubble butt strained his boxer briefs, thick ass meat peeking out of the sides.

Dave decided to be bold and climbed on top of the massive jock, straddling his lower back with some effort. He was getting so big and thick all over, even his lower back muscles. Dave leaned in and rubbed his hands on Grunt’s back, moving up his spine, across the black lettering of the MONSTER tattoo, then squeezing the enormous traps. Dave’s hands felt so small against the thick bulges of muscle he was pressing against. They were so hard, Dave felt like Grunt wouldn’t be able to tell he was rubbing hard, but Grunt sighed and moaned in relaxed pleasure. Dave dug in deeper, using his elbow to press under the shoulder blade and against his traps, rubbing it against the massive MONSTER tattoo on his back. Grunt shrugged his shoulders and cracked his thick neck, and Dave reached up to rub it, running his fingers against the back of Grunt’s mohawk and scalp stubble, feeling his fingers bump over Grunt’s neck folds.

Dave moved his hands down from Grunt’s bull neck down to his shoulders and then over to his triceps. They were thick and hard, more than a handful. Dave rubbed his hands up and down the BIGGER and STRONGER tattoos, marveling at the heat radiating off Grunt’s huge body. Grunt tensed them, the triceps bulging out into a hard horseshoe shape.

Dave was in heaven, feeling every inch of the monstrous behemoth he had created. He rubbed and explored Grunt’s massive back. He shifted off of Grunt’s back and dared to move down to his firm bubble butt, rubbing that too. Grunt spread his legs apart and groaned as Dave kneaded the meaty muscles on his glutes. Dave was rock hard and leaned back to take a breath.

Grunt twisted around and then flipped over to his front. “Can you rub my front too, Doc?” he rumbled.

As Grunt flipped over, Dave’s mouth dropped open as he saw the massive thick cock stretching the boxer briefs Grunt was wearing. It was rock hard, a foot long and thick as a can of red bull, and creating a large wet spot in the boxers. Grunt flopped back down and looked over to Dave with a grin.

“Y-yeah big guy, sure,” Dave said breathlessly and moved closer to the muscle monster next to him. Fuck, he was big. His pecs rose and fell steadily with his breath, so much size packed on. His shoulders were tight, Dave realized as he started rubbing them, breaking up the fascia and making way for more growth. Grunt groaned and closed his eyes, and Dave saw his cock twitch as Dave rubbed harder. Dave moved down Grunt’s arm, feeling the swollen hardness of his biceps, the tightness of the forearms that were bigger around than Dave’s upper arm. A network of veins snaked through Grunt’s forearms; they pulsed with his heartbeat, feeding blood to the growing muscles. Dave took Grunt’s hands, marveling at the thickness of his fingers, feeling the tough callouses on his palms, and massaged them. His own hands seemed so delicate in comparison. Grunt’s huge fingers wrapped around Dave’s, engulfing his hand completely.

Grunt leaned against Dave and grunted.. “Feels so good Doc, fuck,” Grunt said. Dave looked back and Grunt’s cock was throbbing, leaking pre cum through the boxer briefs and bouncing around.

Dave shifted around on the bed, leaning over the massive giant, and rubbed Grunt’s pecs and gut. His belly was hard and full from all the food, and Grunt groaned as Dave worked his hand around, running his fingers through the dense dark fur. Grunt’s breathing got deeper and faster as Dave rubbed, occasionally letting a bassy grunt slip by.

Dave’s hand explored the bottom of Grunt’s belly. It really was growing along with the rest of him, chunky and thick and fat, but underneath Dave could feel the hardness of abdominal muscles. Of course he had a muscle gut, that’s exactly what he needed to be a lineman, Dave thought. He moved his hand down farther…

Until it bumped into the thick cock in the boxer briefs. The big jock grunted and sighed, and his cock switched when Dave touched it.

Dave bumped his knuckle against it. “Feels good, huh big guy,” Dave whispered as he rubbed the massive bulge through the briefs.

“Yeah,” Grunt groaned and his cock twitched again. The wet spot grew.

Dave smiled and wrapped his fingers around the outline of Grunt’s mammoth cock.

“Mmmmmm yeah,” Grunt rumbled and leaned his head back onto a pillow.

Dave shifted his weight to give the giant cock his full attention. He grabbed the elastic of the briefs and pulled it up and over the enormous cock.

“Wow, big guy, you sure are packing down here,” Dave cooed and wrapped his hand around the thick shaft. He could barely get his fingers around it.

“Yeah, always been a big guy, growing even bigger now,” Grunt said.

“Yeah you are, getting so huge. Gonna make the football team for sure,” Dave said and started stroking the big jock.

“Hell yeah, Doc, I’m so huge,” Grunt growled. A bead of precum coalesced on the tip of his cock.

“Yeah just let your Doc take care of you, bud,” Dave whispered and started stroking more vigorously. He leaned down and opened wide, wrapping his lips around the massive, leaking cock head. It was big, the size of a plum, and Dave took the whole thing and went as far down the shaft as he dared as he kept stroking the base of it.

Grunt grunted loudly, his bassy rumble filling the house, as Dave went down on him. Grunt reached down and placed a heavy hand on the back of Dave’s head, pressing him down harder as Grunt’s lust took over. Big jock getting blown by his little Doc friend.

Dave moaned as he choked a little on the thick sausage. Grunt pressed his hand down on Dave’s head harder, and Dave wondered who was really in control.

Grunt leaned into Doc, the tight mouth feeling so good. He had been working up a huge load all day, lifting and eating and lifting some more. He ground his hips against Doc, holding his head in place and fucking harder and harder.

Dave choked again but Grunt kept fucking. Dave realized he couldn’t move his head, the massive fingers gripping his skull, holding him in place. Dave’s own cock throbbed in his pants and he moaned, his mouth full of jock cock, as he shot his load.

Grunt reached climax right after, his massive cock pumping seed into Dave’s mouth, bellowing loudly as he came and came. Dave managed to push his head off the monster cock as he sputtered and choked on Grunt’s cum, only for more jets of cum to splash against his face. He grinned and laughed as he watched Grunt finish cumming, the muscles on the huge jock switching and flexing as he came.

Dave rolled off the bed and used his shirt to mop up the copious volume of cum Grunt had shot everywhere. Grunt looked at Dave and grinned.

“Feel good, big guy?” Dave asked as he rubbed the shirt up Grunt’s furry gut and pecs, wiping up cum.

“Yeah Doc, feel real good. I get real horny when I lift,” Grunt said and he squeezed the base of his cock, forcing the last of his cum out. He wiped it up with a finger.

“Yeah, bud, I can tell, that was a lot of cum!” Dave laughed. “I’d like to keep giving you rubs like that everyday if that’s alright with you,” Dave said, knowing what the answer would be.

“Sure Doc! Whatever you say sounds good to me,” Grunt said as he shifted around to sit on the edge of the bed, his deep voice rumbling Dave’s chest.

“Yup, that’s what I thought,” Dave said with a grin. “Now, who wants dessert?” Dave said. Grunt planted his feet and stood up, the massive giant towering over Dave. He looked down at Dave and smiled as his stomach rumbled, somehow hungry already even though he had just ate several pounds of lasagna.

Part 6

Dave felt something heavy on top of him. The weight of it slowly increased on his chest and midsection until he opened his eyes. There on top of him was Grunt, naked and huge, pressing into him. He could feel his massive cock, thick as a beer can, grinding and rubbing against his furry ass. A huge calloused hand pressed down on his chest, covering most of his pecs. He gasped and tried to squirm but Grunt’s huge weight pressed down on him harder, preventing movement. Grunt’s other hand reached up and smothered his face, covering his mouth and nose.

“Shhhhh, Doc, just hold still, I gotta fuck,” Grunt mumbled and he could feel his plum-sized cock head force its way into his ass. Dave yelled and moaned as he felt the impossibly big cock invade him. Grunt just grinned.

“Yeah that’s right, Doc, I’m so much bigger than you now, you couldn’t stop me even if you tried,” Grunt growled and started pounding into Dave faster and harder. As he did, Dave could see Grunt start to swell bigger, thicker, and taller, laughing and grunting all the while. Dave could feel his ass stretch out more and more and he struggled for breath until…

Dave awoke with a start, panting and gasping for air, the weight on his chest suddenly not there as the dream dissipated. His hard cock leaked precum on the sheets. Grunt wasn’t forcing himself on me, Dave thought with mostly relief but surprisingly a little disappointment as well. He could hear Grunt rummaging around in the kitchen. Dave looked at the clock—9am.

Dave went downstairs and found Grunt right where he expected—in the kitchen, rummaging through the refrigerator, eating whatever he could get his hands on.

“Morning Grunt, how are you this morning?” Dave asked.

The massive jock stood to his full height, his head bumping against the eight-foot ceiling. He had to bend his neck slightly to move around. It had been a couple weeks since he had moved in, and growth had been steady. The kitchen shook as he took a couple steps towards Dave. His mohawk scrapped against the ceiling.

“Great! I’ve been lifting since 5 a.m. Only needed 4 hours of sleep and was full of energy so I decided to lift, but then I got hungry,” Grunt said and grabbed Dave’s skinny arms. He squeezed Dave hard and lifted him into the air, grinning.

Dave tried to respond or wriggle out of the behemoth’s grip, but he couldn’t, suddenly giving him a flashback to the dream he just had. Grunt set him down. Dave was eye-level to the top of his round, solid muscle gut now, he realized. Dave looked down at the massive bulge in the stretchy boxer briefs Grunt wore, then looked up past the watermelon-sized pecs into Grunt’s blue eyes.

“Yeah I bet, big guy, let me make you some breakfast,” Dave said and set about his usual routine of making a breakfast big enough to feed a family, all for his growing test subject.

Grunt sat on the floor—he had already broken most of the chairs in the kitchen and it was clear none of the rest could handle his prodigious 800-pound weight—and watched Dave cook. His expression was blank but happy. His boulder shoulders were pumped from this morning’s workout, and he was damp with sweat. Dave turned around and started cracking eggs to make scrambled eggs for him.

“So, uh, Grunt, I potentially found out why you’re growing so much faster than my trial experiments with mice. You see, the interaction between the myostatin inhibitors and human growth hormone is producing a unique epigenetic phenomenon with your particular set of genes, which is why you’re growing so much bigger than I expected. Isn’t that amazing? You’re a one-of-a-kind genetic freak!” Dave said excitedly. He turned around to read Grunt’s reaction. Grunt’s eyes had glazed over. He looked at Dave with a blank expression, like I was speaking another language.

“Uh, wow that’s great Doc, um, so I guess that means I’m the biggest huh?” he asked and scratched the dark chest fur between his pecs.

“Yes that’s right, Grunt, in a sense, it means even using this on someone else I don’t think I would get the same effect, you’re really quite a unique specimen, even if tried to replicate the study by splicing your genes, but I’m working on a solution to that so it will work on anybody—” Dave began.

“That’s great Doc, uh, but I don’t really get it,” Grunt said loudly, his bassy booming voice overpowering Dave’s. “All that science stuff makes me, um, confused and stuff,” Grunt said as he stood up. He went to the refrigerator and grabbed one of the gallons of milk and cracked it open. “Did you see the replay of last year’s bowl game on TV yesterday? All the other players look so small now! I can’t wait to show them how much bigger I am!” Grunt said with a faraway look in his eyes. He then proceeded to chug the entire gallon of milk, emptying the jug disturbingly fast.

“T-that’s great, Grunt, that’ll be cool… but aren’t you interested in what’s happening to your body? The science here is, it’s, well, it’s unprecedented! It’s a huge discovery!” Dave tried to explain. The sound of the milk jug crumpling drowned out his words. Grunt dropped it on the floor and ripped an enormous, loud belch and then rubbed his prodigious gut. It looked more swollen than usual.

“That’s cool, Doc, but I just don’t really get it. I just know I wanna get bigger and I can’t wait to play football again!” he said and stepped over to the stove next to Dave, his huge shoulder bumping him. Dave could feel the weight and heat of Grunt leaning against him. “Hey, are those eggs done? I’m so hungry…” Grunt said, looking down at Dave over his thick chest.

Dave sighed and shook his head. Grunt really had regressed significantly where he wasn’t even interested in the science, much less capable of understanding it. Dave scooped the dozen eggs he was scrambling onto a plate and handed it to the big jock. Grunt’s eyes lit up like it was Christmas and he started shoveling the eggs into his mouth with his fingers.

“Ah ah, come on big guy, go sit down and use a utensil!” Dave said while pushing his massive bulk towards the table. Grunt had already consumed a third of the eggs on the plate by the time he crashed his butt onto the floor to eat with a fork, shaking the windows of the entire house

Part 7

Dave decided to go check on Grunt out in the garage during his afternoon workout. He had been filling the house with sounds of grunts and roars and clanging weights all day, and Dave found he simply could not concentrate on anything else. He tried to watch Netflix, but he kept missing dialog as rattling weights drowned out the sound. He tried cooking, but the kitchen was right next to the garage and all he could think about was Grunt’s enormous body flexing and swelling and growing bigger. He had tried reading but couldn’t get past the first page of the journal article he had to read for work, his train of thought derailed by Grunt’s bassy growls and grunts as his massive, tireless body did sets that seemed to go on forever.

Finally Dave tossed the journal onto his desk and headed out to the garage. He hadn’t watched the big guy lift in a while anyway, it would be good to check on his progress.

Walking past the pile of dirty dishes in the kitchen, Dave opened the door to the garage, which was closed and dimly-lit. He recoiled for a moment when the smell of the gym hit him, like a hundred sweaty jocks who hadn’t showered in days had been lifting in there. But instead it was just one man, one enormous jock.

Grunt was seated with his back to Dave, his oversized frame making the machine he was using for lat pulldowns seem like it was made for children. He didn’t seem to notice Dave entering the room, as he didn’t slow down in his reps at all. He moved with a machine-like efficiency and rhythm, squeezing the muscle at the bottom of each rep, stretching his long arms as high as could, then crunching back down. They looked like light, easy reps to him, but Dave noticed the machine had the maximum weight plus a couple smaller plates Grunt had jury-rigged onto the weight stack.

Adjusting to the smell, Dave stepped over to a table up against one wall and hopped up on it to sit. He had a nice vantage point from here. Grunt did rep after rep, his set going on for several minutes, before he finally let the weight down. He was dripping with sweat, his too-tight tank top soaked through, the tight boxer briefs with dark sweat patches covering most of its surface.

Grunt stood up and stretched his back and looked in the mirror across the room. He growled and flexed, and his back spread out wider than ever. “Yeah,” Grunt murmured as he shrugged his neck and watched his traps bulge with size.

He turned and noticed Dave in the room for the first time. Even though Dave knew the big lug was harmless and obedient, he still felt a pang of nervousness, or even fear, when Grunt locked eyes with him. He was just so big, so intimidating.

“Doc! How’s it going, bud?” Grunt said and walked over to Dave. He towered over the little researcher, sweat dripping off his body. He stretched his arms to the side, and Dave noticed the lines of stretch marks on his chest, evidence of the waves of growth he had undergone over the last few weeks.

“Oh just fine big guy, great, how are you?” Dave asked. He couldn’t help but be a little nervous and uncomfortable around Grunt. He was the epitome of the kind of jacked-up, thick muscle bro he had always been attracted to, only bigger than any human on earth.

“Great! Lifting feels good today! Setting PRs all over. Maxed out all the machines and weight, but I just do more reps instead.” Grunt said between huffing breaths. His voice had grown deeper and louder over the last couple weeks, and it filled the garage when he spoke.

“Yeah big guy, your muscles look awesome,” Dave said nervously. “C-could you flex your arm?” he asked.

“Yeah Doc, of course!” Grunt said excitedly and stepped closer to Dave. He lifted up his arms and crunched his biceps into a huge flex, the round, solid balls of muscle exploding into rock-hard peaks. “Pretty sweet, huh? They’re so big!” Grunt said with a grin.

“W-wow man, holy shit…” Dave mumbled and reached up to feel the huge bicep. He rubbed his hand over the massive surface. It was bigger around than his thigh, for sure, and much harder. He could feel veins pulsing underneath the skin. It was round and solid.

“Yeah, it’s big! I’m big!” Grunt said proudly as he looked down at Dave.

“W-well, uh, you should keep lifting, Grunt, I’m just gonna watch you for a while. Why don’t you do some bicep exercises?” Dave suggested as Grunt reached for a gallon of pre-made protein shake he had prepped for him.

“Ok Doc, good idea! Want to pump them up even bigger! I bet they’ll look really big with my football jersey on. I just hope I can find pads that fit when the season starts!” he laughed and proceeded to chug the thick, viscous protein shake, his adam’s apple bobbing up and down and his hard, round tummy filling up.

Dave sat back on the table and took a breath, trying to watch Grunt with the objective eye of a scientist rather than getting carried away by lust. Grunt went over and grabbed the 200lb dumbbells from off the rack and started curling them easily, rep after rep, like they were just a warm-up. He stood in front of the mirror, his form perfect, squeezing the round bicep head at the top of every rep. Dave bit his lip as he watched the beast crunch out rep after rep, a machine, his body swollen with muscle. And he was just getting bigger and stronger too, every day, Dave thought as his cock throbbed.

Grunt kept at it for a good 10 minutes, never stopping to rest, just grunting and sweating and curling the dumbbells ceaselessly. Dave knew what a monster Grunt was becoming, but seeing it in person like this, watching him accomplish things no one else could do, was something else entirely. His formula hadn’t just worked, it had transformed Grunt into something more than human. He was perfect, a work of art, a freak of nature, and still growing. Dave squeezed his hard cock to try to relieve some of the pressure, but it just made him more horny.

Grunt finally put the dumbbells down with a thump. He waddled closer to where Dave sat, towards one of the squat racks. The bar was loaded with five 45lb weights on each side for a total of 495. Grunt looked over at Dave with a grin. He was just a few feet from him now, and Dave could feel the heat radiating off the big lineman, could smell his tangy musk.

“Hey Doc, watch this!” Grunt bellowed as his thick fingers wrapped around the squat bar. He picked it up and to Dave’s amazement started cranking out easy reps with it, curling the bar up all the way to his chest, slowly lowering it back down, and then curling up again and again. Up closer, Dave could see just how explosive his strength was now, the weight flying like it weighed nothing, the massive mounds of bicep muscle bunching up with every rep. Dave saw a throbbing vein stand out with every rep. The big man grunted and huffed with every rep, blowing drops of sweat off the tip of his nose, a smattering of sweat droplets pooling on the floor.

Five-hundred fucking pounds, Dave thought to himself, and openly rubbed the bulge in his shorts. It was getting to be too much for him to handle. It didn’t help that the garage seemed hotter and stuffier by the minute as Grunt’s huge body radiated heat; Dave had started to sweat too. He decided to take off his shirt, leaving him in just a tank top and shorts.

The weights rattled as Grunt curled the bar more times than Dave could keep track of until he finally lowered them down with a loud crash. Grunt backed up, panting from the effort, his huge chest rising and falling.

hoooo man that was fucking intense! Feels good! Look at these now, Doc!” Grunt boomed and stepped closer to Dave. He got right up next to him and lifted his right arm up and flexed hard. The massive round bicep bulged up right in Dave’s face.

Dave was speechless. He reached up and put both hands around the huge muscle. Grunt’s skin was shiny and slick with sweat. Dave couldn’t get both of his hands around the incredible muscle, not even close. It was pumped up bigger than Dave had ever seen it.

“Yeah man, feels so good to lift so much! I had to switch to the squat rack last week when the dumbbells stopped challenging me enough for curls. Gotta grow bigger!” Grunt said and showed him his other arm, which was equally huge. His chest and pit hair was matted down with sweat, and his stink was particularly intense up close.

Dave couldn’t take it anymore. He felt like he was going to explode if he didn’t do something. Even sitting on the high table, Grunt towered over him, grinning down at him, showing off.

“Grunt, you’re incredible…just amazing. You’re beyond anything I ever imagined. Y-you’re so hot,” Dave said, breathing heavily, feeling the huge arm. He looked up at Grunt, the vapid grin on the beast’s face one of simpleminded content.

“Thanks Doc!” Grunt said as he lowered his arm and stepped closer to Dave. “I like being the biggest a lot!”

Dave gulped. He knew he wanted this, but wasn’t sure how far he could take it. He had been enjoying rubbing and helping Grunt get off for a couple weeks now, the obedient hulk agreeing to whatever suggestion he had. He decided it was his turn for some fun.

“Kiss me,” Dave commanded. Grunt leaned in and grabbed the back of Dave’s head, pulling him forward and kissing him hard. His beard scratched against Dave’s face, and he thick tongue dominated Dave’s mouth. Their lips pressed together, tasting each other. Dave pushed back after a while to catch his breath. Grunt looked at Dave expectantly, his eyes blank, but mouth curled in a stupid grin.

“Grunt, get on your knees,” Dave said in a firm, strong tone. Grunt nodded and got on his knees, lowering himself down. His face was right at the height of Dave’s midsection, right in front of the throbbing bulge in Dave’s shorts. Grunt looked up at Dave’s eyes and smiled through his heavy breaths, waiting for instruction.

Dave unbuttoned his shorts and shifted around. He pulled them down, letting them fall to his ankles, which hung off the high table. His cock flopped out as he did, stiff and leaking precum. He placed his hands on Grunt’s enormous traps and neck, feeling the dense hardness of his muscles. The MONSTER tattoo undulated atop the bulging muscles.

“Suck my dick,” Dave commanded, and Grunt nodded, licked his lips, and swallowed up Dave’s hard cock in one gulp. Dave sighed and stretched his neck back as the football lineman started working him over, the strong tongue and lips squeezing his cock tightly as he worked back and forth.

Dave leaned forward, breathing harder, and marveled at the sight of this monster—HIS monster—bobbing back and forth, working his cock. Grunt steadied himself on the table, his big hands gripping the edge, and he started sucking faster. Dave watched his enormous shoulders and traps bulging and twitching and flexing as he sucked, felt the bristles of Grunt’s beard tickle his balls.

Grunt started grunting and humming as he sucked, and Dave knew he wasn’t going to last much longer. He looked down again and Grunt’s blue eyes met his own. Grunt’s expression made Dave melt; he looked up with a hopeful, expectant look, as if to say, did I do ok, sir? To think this brute was his to control, the power he had to command… Dave lost it, his cock throbbing as he fired jets of cum into Grunt’s waiting mouth. Grunt sucked it all down fast, the pressure on Dave’s cock increasing as the strong lips squeezed every drop out. Finally Grunt let go and Dave sat back a bit on the table, panting and moaning.

Grunt stood up, once again towering over the little scientist, and grinned. “You taste good, Doc,” he rumbled and licked his lips. He rubbed his own enormous bulge in his tight boxer briefs. “Did I do good?” he asked.

“Oh yeah big guy, that was amazing. Good job,” Dave said through heavy breaths and jumped down from the table. Grunt seemed even bigger and taller once Dave’s feet were on the ground. He pulled his shorts back up and patted Grunt’s chest. He then reached down and cupped Grunt’s hefty package, bobbing it up and down and feeling its weight. “Oh, feels like you need to shoot a load of your own, huh big guy?” Dave said.

Grunt just nodded and sighed, and leaned his tremendous weight against Dave. “Yeah Doc, real bad,” the huge jock said and started grinding against Dave, his cock pressing against Dave’s stomach. Dave was pinned against the table as Grunt started to lean against him harder, his sweat getting Dave’s shirt wet. “Lifting makes me real horny,” he rumbled.

“Alright, alright big guy, I’ll help you out, ok?” Dave said and Grunt looked down at him past his pec mounds and nodded. Dave got down on his knees and nuzzled against the sweaty bulge in Grunt’s shorts. The big guy moaned. Dave had to really kneel straight to have enough height to reach Grunt’s waist, but he managed. He pulled the boxer briefs down and let Grunt’s huge cock and balls flop out. They radiated heat and smelled musky and salty.

Dave stuck out his tongue and licked the massive cock head, savoring the taste of Grunt’s precum. Dave wrapped more of his lips around the head, starting slow, teasing the big jock.

Grunt didn’t have the patience for it though. Dave felt Grunt’s massive right hand wrap around the back of his head and push, forcing him to take as much of the huge sausage into his mouth as he could. Grunt started humping Dave’s mouth fast and hard, his hand pushing hard, his cock jamming down Dave’s throat as far as it could go.

“Helping me grow so big Doc, feels good,” Grunt breathed as he fucked Dave’s face.

Grunt’s animalistic lust took over, the strength of the young brute overpowering Dave so easily. Grunt grunted and growled, lost in pleasure, and Dave just hung on for dear life, trying his best not to gag or choke on the huge cock, thick as his wrist. Grunt moved mechanically, methodically, just like with the weights, thrusting his cock with a machine-like rhythm as the pressure in his big balls increased.

“Little mouth feels good, Doc, feels real good. Such a little guy compared to me now, fuck,” Grunt said. “My cock is so big!”

Grunt thought about how much bigger he was getting. How good his cock felt. How it was going to grow more as he grew bigger. How happy Doc looked, which made him happy too. He kept pounding little Doc’s tight mouth, and he grinned as he looked down and saw him struggle to take his giant cock. He was the biggest! The strongest! So big! He gripped Doc’s hair in his calloused paw and felt his cock start to pulse as cum squirted out. It felt good. He laughed as he came.

Dave sat back as Grunt finished cumming. He had cum running down the sides of his mouth, all over his beard and tank top, and he coughed a bit. He looked up at Grunt who was grinning and squeezing the last drops of cum out of his massive cock. He looked like a real giant from down on the floor.

“That was fun Doc! Felt good. Real good! Love fucking your tight mouth,” Grunt said and stepped closer, bumping his cock onto Dave’s forehead and chuckling.

Dave caught his breath and said, “Yeah bud, that was, really, hooo, amazing!”

“Makes me happy when you’re happy! Can I keep lifting now?” Grunt asked as he stuffed his cock back into his sweat-soaked briefs.

Dave shook his head and grinned at Grunt’s single-mindedness. “Of course, big guy, keep lifting all day!” he said, and Grunt’s eyes lit up like a kid in a candy store.

“Oh boy! Gonna lift all day! Gonna get bigger!” he bellowed as he turned around and started his next exercise.

Part 8

Dave wiped the stove off with a paper towel. The rice cooker clicked as the big batch he was making finished. He grabbed the platter of chicken breasts and set it out on the table with some effort, as it was quite heavy. He tossed out the empty jug of protein powder he had opened this morning and arranged the jugs of protein shake on the table. Finally, we went back to the stove and took the steamer off the main burner, lifted the lid, and started spooning out steamed broccoli into a big mixing bowl.

“Lunch is ready!” he yelled, as the steady clanking he heard from the garage immediately stopped. The floor shook a bit and then the door flew open. Dave looked over at a torso and huge legs filling up the doorway. Grunt’s head and shoulders were totally out of sight, his 9 foot tall body far too small for normal door frames now.

“Oh boy, smells good!” Grunt yelled as he bent down to look into the kitchen. He was breathing heavy and his shoulders and arms looked pumped. Well, everything looked pumped, Dave thought as the giant twisted and ducked as he struggled to wedge himself through the doorway and into the kitchen. After much effort, Grunt managed it and stood—and bumped his head into the ceiling, creating another divot in the plaster and sending dust falling onto the kitchen floor.

“Ow…oops, sorry Doc,” Grunt said sheepishly as he bent over to fit into the room better. The 8-foot ceiling didn’t quite work for the burly jock anymore. The whole house showed signs of damage from the clumsy giant having trouble adjusting to his ever-growing size: the bottom step of the staircase had collapsed in on itself, the beds in the living room were starting to sag already, and of course the ceiling had damage in several locations around the house.

“It’s alright big guy,” Dave said, rubbing the back of his head. Another spot he’d have to fix. He quickly forgot though, looking up at Grunt’s colossal build. He seemed even bigger than he had been this morning. The big jock’s shoulders bulged out to the sides, his broad frame filling the room. His pecs heaved as he breathed heavily, and his musclegut expanded and contracted, alternating between looking swollen and hard and pudgy. His gut was right at eye-level to Dave. He adjusted his stance to make more room for his titanic thighs, thicker around than Dave’s waist and quivering with beefy muscle. His enormous package throbbed obscenely in the too-tight boxer briefs, which were already torn up at where his thighs were thickest. They were the only item of clothing he had left that still fit. Dave shook his head to refocus and said, “Hey, lunch is all ready to go, dig in!”

Grunt’s eyes lit up as he saw the platter of chicken, rice, and broccoli, and he thumped down onto the floor hard, shaking the kitchen. He dug in, cramming a chicken breast into his mouth and ripping it in half with his teeth and hands. Dave had given up trying to maintain Grunt’s deteriorating table manners, and the huge brute mostly ate with his hands. He tried to explain that he was so hungry, he didn’t have time or patience to use forks, but he hadn’t explained it very well. Dave decided it was a battle he was okay with losing. Grunt’s animalistic side seemed to take over when he ate.

Watching Grunt eat turned Dave on immensely. He could put away so much food so quickly, and he was always so focused when he ate, his primal urges encouraging him to eat as much as possible as quickly as possible, his body desperate for fuel to grow bigger. Dave looked over across the table, the beast hunched over his plate, tearing at chicken, only stopping to chug glasses full of thick protein shakes. Grunt didn’t seem to mind that the food didn’t taste all that great; he didn’t even use any sauce on the chicken. He was clearly just interested in consuming as many calories and as much protein as possible to help him grow more.

The chicken breasts disappeared shockingly quickly, even faster than Dave had anticipated, followed by the rice and broccoli. Grunt didn’t say a word, just making eating sounds and breathing heavily through his nose. Dave marveled at the stretch marks that spread across his upper chest and thighs and the ones streaking up and down his gut. That too was growing, especially when he ate a big meal.

After about half an hour, every scrap of food was gone, most of it inside Grunt’s enormous belly. He looked at Dave and grinned, then stood up until his head pressed into the ceiling. He took a deep breath and belched, the sound deep and loud. He chuckled and reached forward with both big hands and rubbed his gut, tortoise shell abs poking through the layer of fat. His sausage fingers scratched through the layer of dark fur coating his gut.

“Feeling good, big guy?” Dave said as he stood up and pressed himself against the huge lineman, rubbing Grunt’s gut in big circles.

“Yeah Doc, real good. Full!” Grunt said as he spread his shoulders and planted himself in front of Dave. He liked the way Dave rubbed his belly after dinner.

“Awesome, that’s good,” Dave said, marveling at the girth and thickness of Grunt’s arms, running his hands over the immense beefy expanse of his forearms and biceps. They made him feel small and weak. Dave could feel Grunt’s huffing breaths snorting down at Dave’s face. “Grunt, we’re gonna have some after-dinner fun now, okay?” Dave said as his hands drifted lower, to Grunt’s massive, wrist-thick cock.

Grunt just hummed and leaned his gut against Dave.

“Grunt, turn me around and fuck me,” Dave said while looking up at Grunt’s square jaw. He had wanted to get fucked for a long time, and he realized if this was going to happen, it would have to happen soon, before the huge jock grew too big. He also knew Grunt was beyond the point of no return mentally, that he would do whatever Dave wanted without question.

Grunt looked down at Dave and nodded. His cock pulsed against Dave’s abs and chest. He tightened his grip on Dave’s arms—his fingers wrapped all the way around Dave’s skinny arms—and spun him around. Grunt tugged at the thin elastic of his boxer briefs, and with a grunt he ripped them apart, letting them fall to the ground. His cock bobbed up and down, free of the confines of the shorts, and it smacked against Dave’s back, smearing sweat and precum on Dave’s shirt.

Dave turned and grabbed the lube he had left out on the counter for exactly this moment. “Grunt, hold out your hand,” Dave said and gestured with the bottle. Grunt obliged, and soon he was rubbing the viscous liquid all around his cock before rubbing it against Dave’s shorts.

“Good good, okay, now, we’re gonna need to take this sl—” Dave began but was interrupted by Grunt tugging sharply at his shorts, trying to tear them apart. Grunt breathed heavily through his nose and grunted, tugging again, his eyes glazed over. He had his orders and a one-track mind, and was horny after his lift. He needed to fuck little Doc, and he needed to do it now.

“Grunt, whoa, just… hang on,” Dave said, pulling his pants down to his ankles, exposing his furry ass. It was a nice round bubble butt, but it looked small and vulnerable next to Grunt’s gigantic form… next to Grunt’s throbbing, swollen, enormous cock. The thing was well over a foot long and thicker than Dave’s wrist. “You gotta loosen me up first, big guy, or else—whoa!!” Dave groaned as two huge calloused fingers shot up his hole as Grunt stretched him out. They moved around inside of him, stretching, pulling, jamming in and out. Dave gasped as they were suddenly removed, and he immediately felt the much bigger cock head rubbing around the warm furry crack.

Dave felt Grunt’s distended musclegut press against his upper back and neck from behind, and suddenly Dave was pinned against the kitchen counter. Grunt growled as he got his legs between Dave’s and easily spread them apart wider. Dave was incredibly turned on if his leaking, throbbing cock had anything to say about it.

“Gonna fuck you good, Doc,” Grunt mumbled and gripped Dave painfully tightly. “My cock is the biggest!” he said and lifted Dave up slightly, bent him over the kitchen counter, and punched into him hard. Dave yelled and moaned, Grunt’s cock bigger than anything he had experienced, and Grunt hummed with satisfaction. “So tight,” Grunt said through clenched teeth and pushed down on Dave’s shoulders, Grunt’s huge calloused hands covering up the entire surface of Dave’s shoulders and traps, his fingers extending down onto Dave’s chest.

Dave gasped as Grunt dug in deeper, waves of pain and euphoria washing over him. He let Grunt manipulate his body however he wanted, not that he had a choice. The massive brute was in total control, physically, as he picked Dave up and sat him on his monster cock.

“You’re so light, little guy,” Grunt said and lifted Dave up higher, pulling Dave up almost off his cock before slamming him down on it again. Grunt’s eyes lit up as he realized how good it felt and how easy Dave was to control. “You’re so light! And I’m so strong!” Grunt said as he started fucking harder. Grunt’s enormous arms bulged with muscle as he lifted Doc’s 200lbs up and down rapidly, the dense hair on his chest brushing against Dave’s back roughly.

Dave was lost in euphoria and pain, but never lost sight of the fact that he was in control and could tell Grunt to stop at any moment. And Grunt would listen. By now he was totally obedient, dependent on Dave for nearly everything. The power dynamics turned him on even more, as he realized the hulking brute was his to command.

Grunt bounced Dave up and down on his cock, lifting him up and down easily, his huge hands digging hard into Dave’s arms and shoulders and squeezing him tightly. Dave couldn’t really think straight, his focus totally on the immense cock ramming in and out of him, its girth stretching him out more than he thought he was capable of.

Grunt huffed and growled and hummed with pleasure, using Doc’s little body to pleasure himself. It felt good to push Doc around so easily. It turned him on knowing he was the biggest and strongest. He felt the pressure on his cock start to build as he backed up from the kitchen counter and kept bouncing Doc on his cock, his arms and shoulders and back muscles tensing with every thrust, holding Doc in place easily, the strength of his body more than capable of fucking his little buddy. Grunt’s head pounded into the ceiling again and again but he didn’t seem to notice. He was too focused on fucking his little friend.

Dave blasted his load all over the kitchen counter right before he felt hot jets of cum fill up his ass. Grunt roared as he came, his deep voice shaking the windows, and cum leaked out and onto the kitchen floor. After a dozen or so spurts, he set Dave down and backed up. Dave felt weak in the knees and had to sit down on the floor, so spent from being fucked by the giant jock. He looked up at Grunt and laughed. Grunt squeezed his cock, dripping more cum onto the floor, and laughed back, both of them basking in the afterglow.


“Dinner is ready!” Dave yelled a few hours later and sure enough, Grunt came bounding in from the garage, looking bigger than ever. He had remained naked after they fucked earlier, and smelled particularly ripe, the dried cum from sex still unwashed. When the big guy came into the kitchen though, he didn’t look at the food. He looked at Dave and walked over to him. Towering over his little friend, Grunt mashed him against the kitchen counter again, his stiffening cock pressing against Dave’s stomach.

“Gotta fuck you again, Doc, it felt so good earlier!” Grunt rumbled and started grinding into him, his massive cock growing fast. He smeared precum against Dave’s shirt and looked down at him expectantly, biting his lower lip, his nostrils flaring, his eyes bulging.

“Grunt, no, we gotta have dinner first and—hey!” Dave started but was interrupted as Grunt picked him up by the armpits and carried him to the living room.

“Gonna fuck you GOOD, Doc!” Grunt said happily, bouncing his now rock-hard cock against Doc’s firm ass, looking forward to how good his big cock would feel in that tight furry hole. “Feels good! Gotta fuck you real bad!” he continued as he threw Dave onto the big bed in the living room.

Grunt loomed over Dave and just as the big lug was leaning over him, Dave said, “Stop! Grunt, no, stop!”

Grunt immediately stopped and stood back up, patiently waiting for direction.

“Grunt, I wanna fuck too, but let’s have dinner first. Then you can fuck me again, okay?” Dave said as he rolled off the bed.

Grunt frowned and adjusted his throbbing, raging hard cock, but nodded all the same. “Okay Doc,” he said, pouting. Dave shook his head at the absurdity of a 9 foot hulking musclebull pouting like a child.

“Now, let’s go back to the kitchen, I’ve got steak and potatoes in there for you,” Dave said, turning the wide lineman around and leading him back to the kitchen.

Grunt looked antsy throughout dinner, eating fast and staring at Dave like a starving man would look at a steak. His breathing got heavier as the meal went on, and he reached down to adjust himself several times. Dave could hear his thick cock thumping against the kitchen floor when he did. Dave smiled and chuckled as the big man struggled to contain himself, knowing he was in total control.

“How is your steak, Grunt?” Dave asked with a grin.

Grunt breathed heavily out of his nose as he swallowed another big bite. “Good. Can I fuck you now?” Grunt said, his one-track mind still focused on sex.

“Not yet, big guy. You gotta finish dinner first, remember?” Dave teased as he took another dainty bite of steak.

Grunt growled and flexed his traps and shoulders as he arched his neck and looked at the ceiling. He grabbed another big steak, ripped it in half with his hands, and then tore into it with his teeth and ate faster than Dave had ever seen before.

Soon all the steak was gone, and Dave started cleaning the kitchen. Grunt went to stand up, but Dave stopped him. “Did I say you could get up? Stay at the table, please,” Dave said patronizingly. Grunt growled impatiently but stayed seated. Dave loved teasing the giant football stud. It turned him on knowing he was in control, totally dominant despite the immense size difference.

After clearing the table, showing Grunt his ass as he went back and forth between the table and the sink, Dave finally stood in front of Grunt. “Okay big guy. You’ve been very patient. You can fuck me n—whoa!” Dave said but was interrupted as the huge brute leapt up, picked Dave up by the waist, and charged into the living room.

Grunt threw Dave onto the bed roughly. The massive jock leapt on top of the little doctor, slamming his weight into him and pinning him to the bed, his cock mashing against Dave’s chest and stomach. “Gotta fuck you NOW, Doc, need to cum NOW,” Grunt growled as he started poking and prodding for Dave’s ass.

Dave tried to remove his clothes but Grunt didn’t have the patience for that. He tore Dave’s clothes off, ripping and tearing and yanking until they were all gone, breathing heavily, desperately seeking Dave’s hole to fuck it.

“Gotta fuck, need to fuck, mmmmmph where is that hole Doc,” Grunt roared as his sticky, slicked up cock mashed against Dave’s still stretched out hole. “Ahhhhh there it is, gotta fuck you bad Doc,” Grunt said as he smothered Dave’s torso with his huge hands and pushed down hard, forcing his giant cock into Dave’s twitching hole. He had more than enough sticky, slimy precum built up to lube things up.

Ahhhhhh yes,” Grunt sighed and started pounding Dave hard, slamming into him mercilessly, his animalistic urges totally in control. Grunt leaned over Dave, whose legs were up in the air, propped up on Grunt’s enormous shoulders. Dave just held on for dear life, trying to withstand the power of a 1100lb+ monster slamming into him repeatedly. His own yelling was drowned out by Grunt’s growls and grunts.

Grunt hummed with pleasure as he fucked and fucked, slamming into Dave, mashing the tight hole, the huge cock crushing in and out. Grunt felt like this was another gym exercise but it felt so much better. He growled as he leaned into Doc and pressed his huge meat paws against Doc’s chest and shoulders, crushing him into the bed. To Grunt, Dave looked so small, so fragile. He looked down at the little guy, whose face was contorted into a mix of pleasure and pain. He compared their sizes and was happy to see just how much bigger he was compared Doc. His arms were bigger around than Doc’s waist, and he was several times as broad and thick as Doc’s diminutive frame. His hands covered ups Doc’s entire torso.

“Unnnngggg fuck Doc, you’re so little. And I’m so big!” Grunt roared. Dave looked up at the monster looming over him, pounding him mercilessly. He could barely see his face, as Dave’s view was taken up by Grunt’s mountainous, hairy, sweaty pecs and bulbous gut, all of which were shaking and flexing and jiggling as Grunt fucked him violently.

Dave groaned, and said “Yeah big guy, you’re the biggest, fuck me, fuuuuuuck me so hard, such a good jock stud.” Grunt bellowed like an animal and came, filling Doc with his hot seed, cum leaking out all over the bed as he came and came before laying down on top of Dave, crushing him into the bed.

Grunt chuckled as he felt Dave squirming underneath him. His skinny body felt so small and fragile, like he could just break it in half if he wanted to. It felt good knowing how heavy and strong he was, and he got off on how much stronger he was, but he didn’t want to hurt the little guy. He’d save that for his opponents on the football field. Grunt rolled off of Doc and stood up again, towering over the little researcher, feeling powerful and strong. He still felt energy flowing through him even though he had been lifting all day and fucked vigorously twice. He felt like he was ready to fuck again or fight someone or smash something or lift every weight in the gym at once. He squeezed his cock, which was already chubbing up harder again, and cum oozed out and onto the carpet.

“Yeah Doc, that was awesome! So hard to wait, but it was worth it. Fucked you good! Can’t wait to fuck you more! Yeah! Gonna start fucking you all the time!” Grunt said excitedly as he picked Dave up and shook him around like a rag doll. Dave yelped in surprise and laughed at Grunt’s antics. Grunt tossed him over his shoulder, then slammed him back on the bed. As he turned to go back to the garage to lift more, his forehead crunched through the top of the doorway separating the living room to the kitchen. He didn’t seem to notice or care. He had lots of energy and needed to lift to get bigger.

Part 9

Dave stood on the back porch, admiring how great his lawn looked. He had Grunt do all his yardwork these days. Save for some divots where Grunt’s enormous weight dug in too deep, it looked perfect. He sighed and a shiver went down his spine and he looked down at Grunt. The giant jock was down on all fours, blowing Dave dutifully. He was naked and sweaty from mowing the lawn. The bulging muscles on his back spread out in front of Dave as his head bobbed back and forth. Dave ran his hands over the MONSTER tattoo that stretched across Grunt’s enormous traps and upper back, savoring the feeling of hard muscle in his hands. He squeezed Grunt’s thick neck, wider than his head and covered in muscle. Dave groaned and put both hands on Grunt’s big skull and thrust forward rhythmically. Grunt’s mouth was honestly too big for Dave’s cock by now, but it still felt good, the strength of Grunt’s tongue doing things to Dave’s cock he could never have imagined.

“Good, Grunt. This feels great. Your huge back is such a turn-on,” Dave said and Grunt hummed in response, flexing his back muscles even more. “Now finish me off,” Dave commanded and Grunt quickened his pace, sucking Dave’s ample cock more vigorously. Dave came with a moan, squirting cum into the giant’s mouth. Grunt was all too eager to slurp it down, as Dave had trained him to.

“Good boy, Grunt. Now you can stand up,” Dave said as he pulled his pants up. The massive lineman planted a heavy foot on the wooden deck, the boards groaning under the colossal weight, and he stood to his full height. He rose up and up, towering over Dave until he stood full 12 feet, 6 inches, twice Dave’s height. Grunt peered over his barrel chest and grinned down at Dave.

“Did I do good?” the giant asked. Dave nodded and Grunt smiled wider. “Hehe, good!” he said, pumping his arms and shifting his weight, excited he made Doc happy.

It was Fourth of July weekend, and Grunt’s growth had accelerated in the past couple weeks. He was truly a giant now, unable to really fit inside the house. The gym equipment in the garage hardly presented a challenge and seemed pathetically small to the big brute. He had switched to using Dave’s car as a weight, which was working well, but Dave knew he would quickly outgrow that too. Grunt mostly lived in the garage, which had a high 15-foot ceiling, and spent more and more time outside in the back yard. There’s weren’t any neighbors close enough to see past the high trees in the back yard.

Dave backed up a few steps and tilted his head to look up at Grunt. He was overwhelmingly big: thick legs bigger around than Dave’s chest, a huge half-chubbed up cock that was as thick as Dave’s arm, a round solid gut, wide, thick pecs that heaved up and down as he breathed, a shelf of muscle covered in dark curly chest hair, wide, round shoulders and traps that merged with his thick neck, bulging arms that fought for space with his pecs and lats and hung out to his sides. Grunt lifted a hand and wiped some cum from his chin, his bicep bulging as he did. He licked his hand clean hummed happily.

“Alright big guy, I’ve got a test for you,” Dave said and Grunt bent down on one knee, listening in like he was in a football huddle. Football and lifting weights seemed to be the only two things Grunt understood anymore, and most of his behaviors were based off those two things. His fist pressed into the ground as he listened, digging into the dirt. Even kneeling, he was taller than Dave.

“See that tree over there? The birch tree in the middle of the yard?” Dave said and pointing to a tree. It was the smallest one in the yard, but he wanted to start with something reasonable. Grunt looked at it and then turned back to Dave and nodded.

“I want you to go over and rip that tree out of the grounds, roots and all. Don’t stop until the whole thing is out of the ground, okay?” Dave said and pointed at the tree.

“Yes sir!” Grunt boomed as he stood up and rushed over to the tree, his long strides making him move fast. He planted himself in front of the tree, and Dave could see the leaves shake as he did. The tree wasn’t that big around, maybe the circumference of a paint can, and Grunt’s two big hands easily wrapped around the whole thing. He crouched down, huge legs bursting with muscle, gripped the trunk tightly, and yanked the tree towards himself.

The whole tree shifted and Dave heard roots ripping up out of the ground. Grunt tugged again, hard, and more dirt flew up as roots erupted from the grass. Grunt shifted the trunk in his hands and pushed the tree the other way, tearing up and away from his body. More of the roots came up. Leaves and sticks fell as the whole tree shook and rattled as he pulled. Grunt chuckled and smiled, then hummed as he yanked the tree again.

Grunt wrapped one arm around the tree, which suddenly looked small and frail next to the giant musclebrute, getting the trunk around his arm like he was putting it in a headlock, and he dashed forward, pulling as hard as he could. The tree cracked and roots ripped out of the ground, the entire root ball coming loose as he charged forward, pulling the entire thing out of the ground. Dirt flew up everywhere, and the tree fell to the ground. Grunt stopped and slammed the tree down as it stretched out across the yard. He picked the whole tree up in his two big hands and brought it down onto his knee, snapping it in half with a roar.

Sweaty and dirty, Grunt looked at Dave and smiled. “Did I do good, Doc?” he boomed as he waddled back over to Dave, his quads rubbing against each other.

“Yeah big guy, that was amazing! That looked pretty easy for you, huh?” Dave asked as he looked up at the giant jock.

“Yeah! I wanna pull up more of those trees! Maybe some of the bigger ones!” Grunt said and adjusted his swelling cock. Using his strength was a big turn-on for Grunt these days.

“We’ll see, bud, we’ll see. Looks like you got a good pump though. Kneel down and let me feel you flex,” Dave commanded, and Grunt obliged.

The huge meathead kneeled so he could be at eye-level with Dave, and he flexed into a most muscular pose. Dave rubbed his hands on the swollen pecs, feeling their hardness and running his fingers through the coarse chest hair, and squeezed the hard density of Grunt’s traps and delts.

“Good, Grunt, good. Feels great. Show me your biceps,” Dave said, and Grunt flexed his big arms in a double bicep pose. Dave felt them, marveled at their size and hardness, felt the thick vein pulsing over the peak. Grunt breathed heavily, his warm breath washing over Dave. He leaned in closer and Dave was overpowered by Grunt’s pit stink, the musky BO emanating from his exposed pits.

“Okay big guy, it’s shower time. It’s been a few days, and you stink, as usual,” Dave said as he walked over to the side of the house to get the hose.

Grunt stood up and followed him, his waddling steps thumping the ground. “Ha, yeah Doc I do stink all the time now! I’m a big sweaty jock giant, can’t help it bro!” Grunt said.

By now he weighed almost two tons; his big feet sunk in the grass and packed down the dirt. Dave couldn’t explain how the big man was still growing so fast; for as much as his constant grocery shopping and cooking, there was no way he had given Grunt thousands of pounds worth of food in the last two weeks. It seemed that Grunt’s body was evolving beyond the need for food and growing on its own somehow. Despite that, Grunt was still always hungry, eating everything he could get his hands on and expanding his big belly.

Dave turned the hose on and started spraying the massive hulk with water. Grunt rubbed the water around his body, washing off the salty sweat and dirt from his body. The water matted down the dark fur covering his chest. Grunt lifted up his arms and Dave got his hairy pits wet too. Grunt leaned down and got his face wet, his chinstrap beard soaking up the water. He blew some of out of his mustache, spraying Dave, who backed up a bit.

“Rotate, time to get your back,” Dave said. The ground shook a bit as Grunt shifted around, showing his incredibly wide back and bulging ass. His butt cheeks were round and powerful, shaking with mass as he adjusted his weight. Dave got up closer to get between the cheeks. “Bend over, big guy,” Dave said and Grunt bent over. Dave was eye-level with his ass and made sure to get in there good. “Okay stand up straight again,” Dave said and he tilted the hose up to get the wide back wet and cleaned off. Grunt ran his fingers through his high and tight, water droplets misting off his short hair. His traps and delts exploded with size as he brought his hands up to his head.

Dave went and turned off the hose and Grunt stood in the yard, dripping and waiting for Dave’s next order. The mental degradation had advanced to the point where Grunt did little without direction from Dave. He lacked volition and counted on his master to tell him what to do and when to do it.

Dave looked up at the behemoth and smiled at his handiwork. And he was still growing bigger every day! His weight gain was in fact accelerating still. He was packing on hundreds of pounds every day now, inching up taller and wider and thicker.

“Well, Grunt, you’re all cleaned off. It’s officially been two months since you started growing. How do you feel?” Dave asked as he tossed Grunt a towel. It looked like a dishrag in his hand.

“Good! Big!” Grunt rumbled as he dried himself off. “Strong too! That tree was small! Wanna tear ‘em all up now!” he said and tensed his muscles and smacked his fist into his palm.

“Yeah? That’s good, because I want the yard clear of trees by the end of the month. How does that sound?” Dave asked as Grunt bent over to dry his legs. He was too thick and musclebound to reach everywhere, and big patches of water still stood out on various parts.

Grunt stood back up to his full height and took a step towards Dave, towering over him. Grunt looked down over his pecs. “Fun, Doc! Can’t wait to show you my strength! Gonna rip ‘em all up!” he said and his cock bounced up and hit Dave in the chin. Dave backed up as Grunt’s cock grew to full mast, swelling up with blood until it smacked the bottom of his gut.

“Whoa there big guy, looks like you’re pretty excited, huh?” Dave said and batted the swollen organ. Grunt flinched and breathed heavy as Dave smacked it a couple times.

“Yeah, Doc. Wanna fuck you bad,” he rumbled and suddenly reached to pick up Dave. Dave rose up in the air, Grunt’s huge hands under his arms, and was pressed against Grunt’s massive chest and gut. Grunt lowered him down until his ass was right on his cock, and he started grinding against Dave’s pants. “You’re so light now, Doc, fuck,” Grunt boomed as he started rubbing faster.

“Wait, no, no no Grunt, you’re too big for that now, remember?” Dave said, staying calm. He knew he was in complete control even though he was being manhandled by his giant friend.

“But I want to, Doc, it feels so good!” Grunt said. “You’re so little now! And your ass is so tight!” Grunt boomed as he lifted Dave up higher and brought him down on his cock again. The huge cock head pressed against Dave’s shorts and threatened to rip right through.

“You don’t fit anymore, remember? Your cock is too thick and you’re too heavy now, big guy,” Dave said. Grunt looked sad. “But you can rub against me to jack off if you want. How about that?” Dave said, less of a question and more of a command.

“Okay Doc, that sounds fun too!” Grunt said as he grinned again and pressed Dave against his swollen cock, rubbing him up and down. Dave took off his shirt and Grunt pressed his cock against Dave’s naked chest, smearing precum into Dave’s chest hair. Grunt started grunting in time with his thrusts, rubbing Dave’s miniscule weight against his nearly two ton body, his huge cock rubbing between Dave’s chest and his own round, hard gut.

“You’re getting so big, Grunt, you just keep growing and growing huh?” Dave said, egging the big guy on.

“Fuck yeah I do!” Grunt growled as his cock spurted out more precum. “I wanna be the biggest!” he said.

“Yeah you are, bud, by far. And what are you gonna do after you cum?” Dave asked as he braced himself against Grunt’s thick forearms. They were solid as rocks and covered with dark hair and throbbing veins.

“Gonna lift,” Grunt breathed as he shook Dave up and down against his cock.

“That’s right. Then what?” Dave said as he was shaken around.

“Gonna grow!” Grunt roared and he started rubbing even faster, his whole body flexing with muscle, his cock veiny and throbbing. “Gonna be the biggest and strongest!!” he grunted, and Dave looked at the BIGGER and STONGER tattoos on Grunt’s huge flexing arms.

“Hell yeah big guy, but is that ever enough?” Dave whispered as Grunt approached climax.

No! Always gonna want more! Gonna become a fucking monster!!” Grunt boomed as his cock exploded, coating Dave with thick white cum, the sticky fluid frothing up between the two of them as Grunt kept shaking Dave.

After a moment, Grunt took a deep breath and set Dave back down again. He was breathing heavily and his muscles looked even more pumped than a moment ago. His massive arms hung at his sides, his biceps bulging with muscle even though they were relaxed. Cum still oozed out of his cock and dripped onto the ground. He stretched and cracked his neck and sighed with satisfaction.

Dave wiped the cum off his torso with his discarded shirt and grinned. Grunt’s cum smelled good, the same musky jock smell as his pungent pits. He looked up at the giant, who had patches of cum all over his chest and gut, and smiled. Grunt had turned out to be the perfect candidate for this experiment, so obsessed with growing bigger, a single-minded lust for more size and power. Power that was totally obedient to him.

“Good job, Grunt. Looks like I’m gonna have to hose you down again, huh?” Dave said as he reached for the hose. Grunt just grinned.

Part 10

August rolled around, and Dave heard the doorbell ring. He wasn’t expecting guests and was in the middle of making lunch for Grunt so he was a bit annoyed as he walked to the door. He opened, and waiting there for him was two men in suits flanked by two cops. He could see two squad cars and a rental car behind them.

“Uh, hello, what can I do for you?” Dave asked as he opened the door.

“Are you Dave Klein? The biology and genetics professor at the University?” said one of the people in the suits, a thin, pale man who didn’t looked he hadn’t been outside of his office all summer.

“Yup that’s me,” Dave replied. “What’s this all about?”

The other man in the suit stepped forward and said, “Dr. Klein, we’re with the Institutional Review Board,” he said flatly and whipped out an identification card. “I’m Agent Jones, and this is Agent McKenzie. We’re here to investigate whether or not you’ve been conducting illegal research outside the purview of the IRB. Do you mind if we have a look around?” he said gruffly and stepped inside, brushing past Dave as the cops, burly men with bulletproof vests and duty belts weighed down by weapons, followed.

“Sure, I’ve got nothing to hide,” Dave said with smirk, moving aside. He had been expecting this for some time. He was actually surprised it had taken them this long.

“Dr. Klein, we’ve received word that you haven’t been to work on campus in almost a month and have been removing certain pieces of equipment from your lab to your house. Is this true?” McKenzie said as he looked around the living room, noting the large mattresses that looked severely distressed or even broken.

“Yes, that’s right, I’ve had a lot going on around the house and some personal issues to attend to,” Dave said.

One of the cops headed upstairs, stepping past the broken bottom steps. “Care to explain what happened here, doctor?” he asked.

“Oh, just an accident, I haven’t gotten around to fixing it yet,” Dave said innocently. “Same with the damage to the ceiling you might see in a couple places in the house,” he said and gestured to a few spots in the living room and kitchen.

Agent Jones was in the kitchen. “Expecting guests? This is an awfully big meal for a man who hasn’t been seen by basically any of his colleagues in a month,” he said pointedly.

“Well, you know, I like to cook big and then have lots of left overs,” Dave said as he checked on the pots of pasta he had boiling, all three of them.

Agent McKenzie approached and pulled out some documents. “Dr. Klein, do you recognize these documents? You submitted a request for funding earlier this year for dangerous genetic experimentation using human subjects based on your prior research involving metabolic process enhancement and biological growth modification. Your request was obviously denied. You haven’t been doing any of this research on your own, have you?” he asked.

“Well, I’m glad you’ve read up on my previous work! I have to say, I’m impressed,” Dave said with a smile as he looked through the paperwork. “Yup, these are mine,” he said and handed them back to Agent McKenzie. “So, what do you guys want to know? What’s this all about?”

The IRB agents looked at each other with a knowing glance. “Doctor, you’re in a great deal of trouble. Doing unsanctioned biological research using human test subjects is… well, it’s highly illegal, not to mention unethical and irresponsible. If the rumors we’re here to investigate are true, you could be facing jail time, not to mention losing your job, your credentials, and any chance of ever—” Agent Jones said, growing increasingly angry.

“Ah ah, let me just stop you right there, ok?” Dave interrupted as he waved his arms. “Look. You guys have been giving me the runaround for years,” he said while turning the stoves off. “I’ve been on the cusp of something stupendous, something that will revolutionize physical therapy, athletics, muscular dystrophy, and more, but you know what I ran into?” he asked rhetorically, winding up into a rant. “Red fucking tape! That’s what! From you! You people are holding me, are holding society, back!”

“Alright, Dr. Klein, let’s just cal—” Agent McKenzie began.

“No! You know what, no! Because I’ve been screwed over by the IRB enough times. And you know what? Yes. Yes, I have been conducting an experiment over the summer, with my own money, right here at home,” Dave said. The cops rejoined the IRB agents and looked like they were ready to haul Dave away at a moment’s notice. They were big guys, all at least 6’2” and much heavier and more muscular than Dave.

“Well, I mean, that’s it then. You need to come with us,” Agent Jones said, shaking his head.

“That’s fine… but don’t you want me show you what I’ve been working on first?” Dave asked with a grin. “Come on out back, I’ll show you,” Dave said and he opened the garage door to lead the way.

Agent McKenzie audibly gasped when he entered the garage, followed by the rest of them. The garage smelled like a locker room and was littered with bent and mangled weight room equipment. Thick, Olympic-grade barbells were twisted into pretzel-like shapes or dramatic U-shaped curves. Most were on the ground but some were hung up high on the walls. In the middle of the garage, a stack of weights reaching up the ceiling sat in a pyramid, like a shrine to the gym.

“How on Earth…what the hell is this, some kind of joke?” Agent Jones asked, annoyed at what seemed like a prank. He kicked aside one of the twisted bars, then reached down to rub his foot. It wasn’t a prop or some light cheap metal, it was thick steel.

“Just follow me, out this door,” Dave said airily, smirking at the shocked and confused faces following him. He opened the door from the garage out to the back yard, and walked out into the yard.

The back yard wasn’t what it used to be. The grass was torn up in several places and the many trees that had once dotted the space were gone, seemingly torn up and stacked against a fence on the far side of the yard. Mangled roots still stuck out from the depressions in the ground where trees had once stood. They looked like they had been forcibly ripped out of the ground by a truck or something.

“Grunt! Come on out, bud, we’ve got visitors!” Dave called out.

Something grunted on the far side of the house, a deep bassy sound, followed by an ominous thump. The ground vibrated a bit under Agent Jones’ feet. He looked up and his mouth dropped open.

Grunt came around from the side of the house where he had been doing pushups in the side yard. He was stupendously huge. He had grown even bigger, thick muscles bulging all over his body. His traps swelled up thick and engulfed his neck, his delts stood out to the sides like bowling balls. His arms bulged with muscle, biceps and forearms swollen and pumped, leading down to huge hands that clenched into enormous fists. His huge barrel chest was marked by a pattern of stretch marks, covered in dark fur and capped by meaty nipples. Grunt’s big belly bounced and jiggled as he sauntered over to the group, fat and huge but solid if you looked close. His cock was at a half-chub and bounced against his thick meaty thighs as he walked. Dave and the IRB people barely came up to Grunt’s knees; they had a great view of his bulbous calf muscles and huge feet. Dave looked up at the big lineman and smiled. Grunt’s eyes were blank, but he had a slight grin as he looked down over his chest and gut at the group, a day’s stubble on his cheeks, his beard trimmed into a thin chinstrap and his hair shaved into a short Mohawk. The ground shook hard as the giant planted himself in front of the group in a wide stance.

“Grunt! I’d like you to meet the folks from the IRB,” Dave said.

Grunt just smiled wider and scratched the fur on his chest.

“Jesus Christ, how the hell did this happen!?” Agent McKenzie said breathlessly, craning his neck to look up at the behemoth towering above him.

“My formula,” Dave said simply. “It worked perfectly on the big lineman. He came to me wanting to get bigger, and I was only too happy to oblige. His desire for more size, genetic background, and pre-existing combination of muscle and fat were the perfect catalysts for explosive growth. Grunt, how tall are you these days anyway?” Dave said and patted the giant on the knee.

“25 feet tall!” he boomed, his voice loud and deep. He took a breath and straightened to his full height, his face disappearing behind a wall of pec muscle as his chest expanded.

The cops and Agent Jones shifted uncomfortably, suddenly acutely aware of how outmatched they were.

“And what’s our best guess at how much you’re weighing these days, big guy?” Dave continued, enjoying the uncomfortable looks from the rest of the group.

“Thirteen tons!” Grunt rumbled. He shifted his weight and the ground shook slightly, emphasizing his enormous tonnage. “Growing bigger everyday, too!” he said and jiggled his big belly. “I’m real strong too!” Grunt boomed and flexed his biceps, showing their massive round peaks.

Dave smiled at the shocked expressions on the IRB agents. “Grunt, what other kinds of changes have we noticed since you grew bigger?” Dave asked the flexing giant.

“Well, I never get tired anymore, I can just lift and lift for hours. Don’t really need to sleep or eat much, though I still love eating, haha!” Grunt intoned and smacked his gut. “My cock is way bigger too and I’m always horny,” Grunt growled and brandished his thick dick.

“Heh, that’s great, big guy. Grunt, I think our guests would love to see a demonstration of your strength. I’ve been saving this one for a special occasion just like this. You know the last tree in the yard?” Dave asked, pointing to the huge silver maple in the center of the yard. It was enormous, 40 or 50 feet tall with a trunk so thick Dave couldn’t even wrap his arms halfway around it.

Grunt shifted and looked over at the tree. “Oh yeah Doc, I wanna rip it up!” Grunt said excitedly. Dave knew he had been wanting to do just that for weeks, but he told the big guy to wait.

“Well today’s your lucky day, you big lug. Rip it out of the ground and show our guests just how strong you are!” Dave said.

Grunt roared in excitement and moved disturbingly fast, charging the tree. Jones and McKenzie yelped and jumped back as the giant exploded into action, and the cops both grabbed their guns. Grunt charged at the huge silver maple and slammed into the thick trunk, shaking its leaves and sending sticks and branches tumbling down. The trunk of the tree crunched and popped as it buckled from the impact.

Grunt squatted down below the branches of the tree, growled, and wrapped his huge hands around the trunk, wrapping partway around it. He planted himself in front of it, his broad back spreading and tensing, the muscles dancing underneath the MONSTER tattoo on his upper back. He squatted down slightly, massive thighs bulging, feet sinking deep into the grass as his tonnage pressed into the ground, and then suddenly exploded with force out and up.

“GONNA RIP IT UP!” he roared excitedly and he felt the tree start to give way. He stood up and wrapped both of his arms around the tree, breaking past branches and sending them falling to the ground, causing Dave and his guests to back up. Grunt gripped the tree in a bear hug and growled as he pulled up. The ground shook as roots started to tear out of the ground. Grunt pulled again, harder this time, grunting loudly, and the tree made sickening cracking sounds. Grunt stepped back, bent down and wrapped his huge calloused hands around the base of the tree and pulled hard again, and this time the weakened tree tore out of the ground completely. Roots ripped up out of the ground from all over the yard, sending grass and clods of dirt flying.

“YEEAHHHHAAA FUCK YEAH!” Grunt boomed as the tree tore out of the ground and fell over. Grunt followed through by tackling the tree to the ground. The tree and the giant boomed to the ground, their combined tonnage making the ground shake. Leaves and branches scraped and rustled against the ground and broke the fence as they fell. Grunt brought his fists together and crashed them down on the trunk of the tree, splintering the wood as he laughed and yelled.

“YEAH DOC DID YOU SEE THAT?” Grunt said as he bounded to his feet and punched his fists together. “FUCKING DESTROYED THAT SHIT!” the big jock boomed as he rumbled over to Dave and the IRB folks.

Part 11

Awesome job Grunt!” Dave said. “Go ahead and have a seat,” he said and Grunt immediately crashed down in front of them, breathing from his excitement, muscles twitching. His huge ass shook the ground as he sat down heavily.

Dave turned to the terrified IRB agents and the on-edge cops. “You see how powerful he has become? My formula has unlimited potential to increase strength, augment size and enhance muscle growth. As an unexpected side effect, Grunt has become totally obedient to me and is pretty much dumb as a rock. He hardly thinks for himself beyond wanting to grow more and please me,” Dave explained. “Let me show you.”

Dave turned back to Grunt, who was flexing his bicep and feeling the hard mound of muscle. “Grunt, great job!”

Grunt stopped feeling his muscles and looked down to Dave, his mouth open slightly. “Thanks Doc! Glad you liked it, ripping that tree up felt good!” he boomed.

“Grunt, I have a question for you. What’s two plus three?” Dave asked.

Grunt’s face slowly went from happy to bewildered, and he looked up, suddenly in deep thought. “Ummmmmm,” he said, scratching his head with his big right hand, causing his huge bicep to bunch up. He counted with his fingers on his left hand. “Math is real hard, Doc. Is it six?”

Dave chuckled a bit. Agent Jones gave him an uncomfortable look. “Nope, sorry bud, but that’s ok. Hey, can you reach over and grab the hose?” Dave asked. Grunt reached over to the side of the house past the deck and plucked the hose off the ground.

“Ok, now I want you to raise the hose over your head and get yourself wet, ok?” Dave said. Grunt lifted the hose up. Dave went over and turned on the spigot, and water poured down on top of the giant. Grunt shivered and huffed as the water washed over his naked body. He tried to lick some of it up as it cascaded over his muscles. Dave turned off the water.

“Good! Now rub your belly,” Grunt rubbed his belly, spreading the water over his gut and getting his hair into wet ringlets, the expansive gut jiggling. “Now bark like a dog,” Dave said, and Grunt woofed loud and deep, making the IRB group flinch. “Show us your tricep tattoos,” Dave said, and Grunt twisted his arms forward and flexed his triceps, showing the bold, black BIGGER and STRONGER tattoos that looked stretched and warped over his huge muscles. “Now flex your biceps and show us how huge you are,” Dave said. Grunt brought his arms up and flexed, the smell of his armpits making Agent McKenzie wrinkle his nose, biceps exploding into mountains of muscle. Agent Jones heard something scraping against the ground underneath Grunt’s huge gut.

“I got real big muscles, hehe,” Grunt intoned as he looked down at Agent Jones. Grunt shifted his weight as something swelled up bigger under his gut and against his thighs.

“Grunt, I want you to smash the deck as hard as you can with your fists,” Dave ordered, and Grunt obeyed without hesitation, bringing both huge fists down on top of the deck with a bellow, smashing it to bits. The cops lifted their guns up and the agents jumped back. Grunt just chuckled at their reaction. He reached down to adjust himself, his huge hard cock ripping up dirt and grass as he pulled it out from under his belly. He sighed as he freed it, precum oozing onto the grass. Showing off his strength and size and obeying little Doc had turned on the big jock.

Dave turned to the visitors. “You see? He’ll do anything I tell him to, and obviously he has incredible strength. He’s stupid, but obedient, and that’s a benefit, if anything. Imagine how interested the military would be in an army of Grunts, obeying every order without question, an unstoppable destructive force. And Grunt is just the prototype. He’s still growing bigger and stronger every day, I don’t even know when he’ll stop growing. And you like growing bigger, don’t you Grunt?” Dave asked.

“Fuck yeah!” Grunt boomed and his cock throbbed harder. “Growing bigger every day!”

Agent Jones shook his head. “This is… this is a disaster. This is the most egregious violation of ethics I’ve ever seen. You’ve ruined this poor young man’s life, not to mention created a danger to society as we know it. Your formula is an abomination, and the risks we warned you about are on display right here in front of us. He’s a monster, and so are you. Doctor Klein, you’re under arrest and you’re coming with us,” he said and motioned for the cops to grab Dave.

“You’re joking, right? Did you miss the part about me having an obedient giant right next to me who will do whatever I tell him to?” Dave said, scoffing at the IRB agent’s threat.

The police officers hesitated, looking up at the seated goliath towering over them. Agent McKenzie shoved them forward. “Listen to your superior officers, arrest him!” he said.

The cops stepped towards on Dave, guns pointed.

“Grunt, squash these guys,” Dave said calmly.

The giant moved faster than the cops thought possible, his huge legs shifting and thumping into the ground as he stood to his impossible 25 foot tall height once again. He looked down at the cops angrily, tensing his pecs. “Hehe, gonna squash you, little cops!” he boomed, and he leaned down to take a swipe at them. His massive fist moved fast, faster than either of them expected. One cop dodged out of the way, but the other stood his ground and fired. The bullets bounced right off the giant, and Grunt’s huge fist connected. The cop yelled and flew across the yard, landing 20 feet away. He groaned as he landed, clutching his broken arm.

Grunt smiled at his handiwork then looked down at Agents Jones and McKenzie. He lifted up a huge foot over them and moved to crush them, but the IRB agents and both cops started running towards the exit. Grunt roared and stomped after them, destroying what was left of the deck, thumping the ground hard as they fled into the garage.

Grunt straightened up and rolled his neck, feeling his traps and neck muscles fight for space. He smacked his right fist into his left hand as he looked down at Dave, waiting for direction.

“After ‘em, big guy, show them how strong you are and that we are not to be messed with,” Dave said, feeling a rush of power ordering around his own personal hulk. Grunt nodded and stepped quickly around the garage, crashing through the neighbor’s fence that only came up to his shins.

The IRB agents and cops rushed out to the front of the house, making their way back to their cars, hearing and feeling Grunt pursuing them. Agent Jones looked back and saw the giant rounding the garage and spotting them, his massive body tensing in excitement as he saw them trying to get away, his thick cock pulsing and flopping around between impossibly thick thighs. “THERE YOU ARE,” Grunt said. “I’M GONNA SMASH YOU!” he boomed and started for them.

“Jesus Christ, start the car, start the car, we have to go NOW!” McKenzie said as he got into the passenger side. The two cops went for their squad car, but the injured cop was moving slow, clutching his broken arm, blood soaking into his uniform.

Grunt roared and charged towards them, his legs propelling his massive bulk forward fast. He slammed his foot and shin into the cop car before the officers could get to it. The car crunched with a sickening metal squeal as it flew and spun into the air and landed in the yard across the street, broken glass flying everywhere. Grunt followed it, thumping across the street and grabbing the car, which seemed so small next to his massive body. He lifted it up and slammed it down once, twice, three times until it started completely breaking apart. He growled and grunted as he did, letting his aggression and power flow through him as he tore the car apart until it was little more than scrap. He bent it over one of his thighs and snapped the frame in two, then crushed the sides together, crunching the metal, pressing it between his hands and against his hairy chest, smashing it into debris.

Agent Jones and McKenzie looked on in horror as they beckoned for the cops to get in to their car. They turned the engine on, which got Grunt’s attention. He looked across the street, his face a picture of rage and glee, his simple mind enjoying the destruction and wanting more.

He tossed the twisted metal of the cop car aside and grinned. “I’M GONNA CRUSH YOU!” he roared excitedly just as they pulled away. He charged after them, bounding down the street in huge long strides, his feet tearing divots into the concrete, catching up with them quickly. He reached forward and pounded a huge fist into the trunk of the car, making the car bounce and leaving a huge dent in the in the car. Grunt laughed an ominous, booming laugh as he reached forward to grab the car and crush the four helpless men inside.

“Grunt, stop!” Dave yelled as he got to the front yard. Grunt stopped chasing and watched the car drive away. “Let them go! It’s fine,” Dave said as he walked out towards Grunt. Grunt turned around to face Dave and straightened to his full height, his chest heaving, his muscles flushed and pumped, sweat dripping from his nose.

“Doc, they got away!” Grunt boomed as he walked back to the house. “Why did you let them? I wanted to crush them! I was bigger and faster than all of them!” Grunt said as he adjusted his still-swollen cock.

“I know bud, and you did great. You made me proud! But it’s time for us to move on anyway. This house is too small for you now, and we need to go somewhere where we can continue our research in private. Somewhere you can grow even bigger without people bothering us, somewhere I can perfect my formula in peace without their interference. I’ve already made arrangements out in the countr—whoa!” Dave said but was interrupted by Grunt lifting him up off the ground, his big hands gripping his tightly under his arms.

“I did good, Doc? Really? You’re proud of me?” Grunt said, grinning at Dave as he lifted him up to his face. “I did good! I’m glad I made you happy, Doc!” Grunt said as he started rubbing the diminutive researcher against his sweaty, hairy chest and lowering him down towards his throbbing cock.

“Y-yeah Grunt, very happy, I, oof, hey, watch it!” Dave said with a laugh as Grunt started rubbing Dave against his massive cock, the huge head the size of a basketball. It bumped against Dave’s butt, smearing precum on his shorts.

“Hitting that guy and wrecking that car were such a rush, Doc! I’m so strong! Using my strength makes me real horny!” he grunted as he walked back to the house, his cock throbbing as it bumped against Dave’s ass.

“Alright big guy, let’s go take care of this before we head out to the country,” Dave said, rolling his eyes at the simplemindedness of his giant jock friend.

“Yeah! Gonna cum all over you, little guy!” Grunt said as he walked around the garage and into the back yard, carrying his little buddy like a prize.

Epilogue

The truck Dave rented was big enough to carry Grunt and most of their essentials away from the house and out to the farm that Dave had been getting ready for the better part of a month. It was an old family farm that had been passed down to him. Dave had rented the land out even since he inherited it years ago, but recently decided to get it ready for an eventual move for him and Grunt. He knew he couldn’t keep Grunt in his suburban neighborhood, not once it became clear that he was going to keep growing into something beyond normal human limits.

The idea was for him to continue his research in the privacy and seclusion of an out-of-the-way place, far from the prying eyes of most people where he could study Grunt’s tremendous growth, perfect his growth formula, and live simply with the giant stud. And that’s exactly what he did for a year after they fled, converting the basement into a decent lab. Grunt lived out in the barn, the enormous old building big enough to comfortably house him at night. He no longer needed food or sleep, but loved eating as much as he could and tended to sleep when Dave wasn’t awake to give him orders.

Grunt was all too happy to move to a bigger place where he’d have more open space to himself, plenty of physical labor to do, and no other responsibilities other than working, eating, watching football, lifting, growing, and fucking. His mind had been distilled down to these basic needs and he rarely thought of anything beyond that.

Dave watched the sun set from his porch and sipped on a beer. He looked over the latest version of his formula on his tablet, smiling at the progress he’d made over the past year, free of regulations or ethics. The formula was perfect, capable of turning any man into a muscular giant, and he was toying with what to do with it. He was lost in thought when the wooden porch started the rhythmic shaking he was used to hearing around this time of day. Rumbling, booming thump thump sounds echoed around the open fields, getting louder and more intense. Something huge was coming his way. His big jock buddy, back from a day of working in the field, clearing away forests for firewood and to make way for more fields.

From behind the copse of trees on the northern edge of the property, Grunt appeared. His belly brushed against the tops of the trees as he waddled his way back to the house, his massive frame heavy and thick with muscle and fat. He had grown thicker and hairier since last summer, and sported a full beard of dark hair and a shaved head. He was naked, and his cock swung pendulously between his legs, his package rubbing between the thigh muscles as he walked. His steps shook the ground and covered a lot of distance, and he moved frighteningly fast. He towered over the two-story farmhouse as he approached Dave. He grinned down at Dave, his eyes glassy and unfocused, his mouth slightly open. He planted himself in front of the house, which shook and creaked as 200 tons of football lineman beef towered over it. The house didn’t even come up to his waist.

Dave craned his neck to look up at the nearly 65 foot tall giant. Grunt had just kept growing and growing once they moved out to the country. For a while Dave was worried he would never stop growing, always getting bigger and bigger, but around December he had finally slowed and stopped packing on size. Grunt had been sad when he stopped growing, but he listened to Dave and obeyed him without question and was glad Dave could proceed with his research. Dave needed Grunt’s growth to stabilize in order to isolate the causes of his explosive growth and perfect the formula.

Dave put his tablet down and pulled his pants down, freeing his hard cock. He looked up at the giant. “Flex,” Dave commanded. Grunt brought his fists together and flexed his arms and chest, his biceps bunching into massive peaks, his pecs bulging up and out like mountains. His traps and shoulders swelled up bigger and harder, and he grinned down at Dave. Dave started rubbing his cock vigorously, marveling at the size and muscle of the giant. It never got old watching the big jock flex.

“Turn around,” Dave said, and Grunt turned, the earth shaking under his tonnage. His ass bounced and jiggled as he shifted his weight. His mighty back now faced Dave, whose mouth dropped open in wonder. “Flex your biceps,” Dave said simply, and Grunt flexed. His arms rose up in a double bicep pose, mounds of muscle erupting from his back. The tattoos on his arms and back were never more accurate, as the biggest, strongest monster on Earth flexed and grunted, his deep grunts echoing through the fields.

“Who’s the biggest monster on earth?” Dave asked as he jerked his cock faster, nearing climax as he watched Grunt’s lats swell wider.

Grunt’s voice was like thunder. “I AM,” he boomed ominously, the volume of his great voice making Dave’s ears ring.

“And who do you have to thank for that?” Dave asked.

“YOU, DOC,” Grunt rumbled as he turned around to face his master.

Dave’s breath increased as he jerked faster. “Call me sir,” he said.

“YES SIR!” said Grunt, who flexed more as his own cock stiffened, watching his tiny master jerk off to his immense body. He loved making his master happy.

“That’s good, Grunt. My big jock giant. All mine,” Dave breathed as he neared climax.

“YOUR GIANT TO COMMAND, SIR. THE BIGGEST!” Grunt boomed and he straightened his shoulders and swelled his chest out. He towered over Dave, the house, everything in sight. He brought his hands together and flexed again, his gut jiggling, his muscles bulging with power. He reached down and started stroking his own rock-hard cock, his muscles flexing and tensing as he stroked himself. “I’M SO HUGE!” Grunt rumbled as his muscles tensed and he erupted, cum spraying all over the roof of the farmhouse, shooting out into the field on the other side of the house. He roared as he came, and his voice echoed across the fields loudly.

Dave shot a thick load of his own as his giant, obedient meathead towered over him, and he smiled.

Description Dave, an ambitious researcher at a well-known university, hires an eager-to-grow football player to test an experimental growth supplement. The experimental growth supplement works much better than anticipated and Grunt gains over 50 pounds in just a week, though with some troubling side-effects.

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