The lab rat

by Beastly Muscle

A scientist makes a medical breakthrough with a newly-made drug that promotes muscle growth. As the drug is in its testing phase, the lab rat being experimented on gets a unique opportunity.

In the sterile confines of a modern laboratory, Dr. Ethan James, a brilliant scientist, embarked on a groundbreaking experiment. His subject: a humble lab rat named Squeaky. Dr. James’s goal was to test the efficacy of a newly developed muscle growth drug.

Meticulously, he administered a single pill to Squeaky each day, carefully monitoring its gradual effects. Days turned into weeks, and Squeaky’s physique underwent a remarkable transformation. With each passing dose, his biceps swelled like ripe melons, his pecs expanded into a formidable chest, and his quads and calves grew as thick as tree trunks.

But fate took an unexpected turn. One fateful afternoon, as Dr. James was momentarily absent from the lab, Squeaky’s keen senses detected the tantalizing scent of the remaining pills. Unable to resist the allure of further growth, he seized the opportunity and consumed them all.

Instantly, Squeaky’s body erupted in an explosion of muscle mass. His biceps began to bulge like cannons, his pecs exploded with size and threatened to burst through his skin. His quads and calves grew so immense that they resembled those of a behemoth. Even his glutes swelled to powerful proportions, becoming spheres of pure muscle the size of basketballs.

As the growth intensified, Squeaky’s manhood became engorged and throbbing. His testicles swelling to the size of grapefruits while his dick grew longer and thicker by the second. An overwhelming surge of horniness coursed through his veins, and he began admiring his newfound strength while massaging the head and shaft of his colossal dick. He came as he stroked his cock and ushered in another wave of growth.

Driven by the primal urge of new growth, he strained against the confines of his cage, his muscles rippling beneath his skin. With a deafening roar, Squeaky grabbed the bars of the cage and began pulling them apart, his muscles effortlessly shattered the steel bars of his prison. Freed from his captivity, he continued to grow exponentially, towering over the laboratory with his colossal frame.

He hungered for more growth and tore the lab apart looking for more of the growth pills. He could not find any more of the pills in his rampage and decided to await the scientist’s return, hopeful that he would bring more fuel for his growth. As he waited, his growth slowed and Squeaky settled into his new size. Hours passed as Squeaky explored his new body, feeling the heft of his pecs, the girth of his biceps, the roundness of his glutes, and the astonishing weight of his leaking cock. Squeaky soaked the floor of the lab in his precum while feeling himself up as he waited patiently for Dr. James’s return, hungry for that intoxicating feeling of growth.

Finally, the scientist entered the lab, his eyes wide with both awe and trepidation as he beheld the beast of pure muscle before him. Squeaky rushed to Dr. James, seizing him by the waist and lifting him effortlessly into the air. With a guttural growl, he pinned Dr. James down, his massive thighs crushing the man’s resistance. Dr. James attempted to struggle to escape the hulking beast pinning him down, but to no avail. There was no escape, and the scientist knew this, but despite how scared he was he still began to sport his own lustful erection.

Dr. James had left the lab to retrieve more of the pills, and Squeaky noticed when he smelled the scent of the drug in the scientist’s lab coat. Squeaky grabbed the bottle of pills out of the lab coat of the scientist as Dr. James stared at him awestruck. He secretly wanted this musclebound beast to blow up in size even more. Squeaky ripped open the top of the bottle and in one swift motion swallowed the entirety of the bottle’s contents. As Squeaky’s muscles flexed and bulged, his manhood grew erect to an astonishing size. He tore the pants off the scientist and thrust into Dr. James with animalistic force, his groans of pleasure echoing through the laboratory.

Hour after hour, Squeaky dominated the scientist, using his newfound power to fulfill his insatiable hunger for growth. With each thrust, his muscles grew larger and more powerful, until he had transformed into an unstoppable force of nature.

Finally, exhausted but triumphant, Squeaky released the scientist and watched as he collapsed to the floor in the puddles of cum from both of their emissions. As the adrenaline subsided, Squeaky realized the true extent of his power. He had not only broken the chains of his captivity but had also become an apex predator.

From that day forward, Squeaky roamed the world hungry for growth, his colossal physique a testament to the indomitable spirit that resided within him. And though Dr. James’s experiment had gone awry, Squeaky carried with him a legacy that would forever be etched in the annals of science.

Vote on this story

The box by BRK Steve gets a box of clothes from his mysterious and beautiful brother, Peter, and it turns out the clothes have an amazing effect on his already unusual body. 8 parts 30k words Added Dec 2002 Updated 7 Sep 2019 34k views 5.0 stars (14 votes) No comments yet •Cock Growth•Huge Cock•Public Orgasm•Extra digits•Multicock•Multihead•Four Legs•Multiarm•Multileg•Multilimb•Replication•Muscle Growth•Stretchy•Getting Handsomer•Getting Taller•First Time/Virgin•Incest•Brothers•Selfcest•Witch/Warlock/Wizard •M/M•M/M/M•M/M/M/...

The cock-off by Armie Lingo In the gym locker room, Nick and Joe get the chance to admire Cock-Off champion Steve up close. 3 parts 5,295 words Added Oct 2005 27k views 5.0 stars (14 votes) No comments yet •Cock Growth•Huge Balls•Huge Cock•Hyper Cock•Hyper Cum•Muscle/Strength •M/M•M/M/M

Ladder of the heavens by Ziel "Someone suggested that I do a story with piercings and jewelry that caused growth in the owner. I made use of some other suggestions as well so this story features a wide array of kinks including muscle/dick growth and even a touch of shrinkage, and there’s even a cute little *spoiler* with a *spoiler**spoiler*" 11k words Added May 2015 19k views 5.0 stars (4 votes) No comments yet •Cock Growth•Huge Cock•Hyper Cock•Muscle Growth•Muscle/Strength•Pointy Ears•Size Decrease

The new associate by Tym Greene Zhu is looking forward to his first day a new architectural firm, sure the way he grows—and makes other people grow just from being around him—will make things very interesting. 3 parts 13k words Added May 2015 Updated 12 Dec 2020 41k views 5.0 stars (2 votes) No comments yet •Cock Growth•Huge Cock•Hyper Cock•Muscle Growth•Muscle/Strength•Public Nudity•Size Increase•Tongue Growth•Father/Son•Anthro/Furry •M/M•M/M/M

Student body president by BRK Being a warlock at school can be a pain—especially if everybody knows. 2,906 words Added Sep 2004 26k views 5.0 stars (4 votes) No comments yet •Cock Growth•Huge Cock•Self-suck•Multicock•Muscle Growth•Muscle/Strength•Stretchy•Size Increase•Witch/Warlock/Wizard•Complete

Stuff in the cellar by Charles Westfall Richard is already good-looking and abnormally hung when he discovers some alien equipment in the cellar of his new house—including a vat of goo that transforms him into someone even hotter and more hung. And there’s no way Richard’s keeping his new gifts to himself. 4 parts 15k words Added Jul 2002 25k views 5.0 stars (9 votes) No comments yet •Cock Growth•Huge Cock•Hyper Cum•Muscle Growth•Muscle/Strength•Pointy Ears•Size Increase •t/t•t/t/t

Twinning: The college years by BRK At college, Will attracts the attention of a sexy, Irish hockey player who pushes all Will’s buttons—but now that he’s in this new world Will isn’t sure he can share all of himself with his slowly growing admirer. 8 parts 37k words Added Mar 2017 Updated 9 Oct 2021 29k views 5.0 stars (11 votes) No comments yet •Always Hard•Cock Growth•Huge Cock•Hyper Cock•Self-suck•Extra digits•Multi-abs•Multicock•Multitongue•Replication•Muscle Growth•Muscle/Strength•Always Shirtless•Getting Taller•Size Increase•Tongue Growth•Selfcest•St. Patrick’s Day •M/M•M/M/M/...

Charlie and Frankie’s exciting new experience by Charlie Frazer Two friends go into a strange store that turns out to offer latex monster cocks, complete with a demonstration from the shopguy of exactly how well they function. 1,331 words Added Feb 2018 11k views 5.0 stars (13 votes) No comments yet •Cock Growth•Transformation•Rubber/Latex •M/M