Mass Overdrive

Patreon-exclusive Halloween Special🎃

A storm had been raging for hours, and even three stories beneath the surface, the sounds echoed inside with such force that the walls shook with every thunder. Every few seconds, the lights flickered with each lightning strike, and a cold rush of wind entered through the ventilation shafts as the world above seemed to fall apart.

Evan walked through the underground facility, barefoot, and only wearing a pair of loose gray shorts that barely clung to his narrow hips. At 22 years old, he was barely five feet tall and almost so painfully thin that his collarbones jutted beneath his pale skin. His shoulders were narrow, and his ribs were visible whenever he inhaled. His arms had no muscle mass, lacking the thickness he had always longed for, and his legs seemed almost too thin to support him. His frame was fragile, nearly delicate, like a sketch of the man he wished to become.

He took deep breaths, walking through the halls as casually as possible, but the anxious shake in his hands betrayed how he felt. He followed the two scientists who worked there into the lab, secretly admiring how tall and thick they looked even under their lab coats. When they entered the lab, Evan’s blue eyes widened as he scanned the place. The polished steel consoles gleamed beneath cold fluorescent light, and cables snaked across the floor, leading to the centerpiece of the chamber: a glass-and-metal pod tall enough for a man to stand within.

Dr. Carlson, the lead scientist, turned to give Evan some final warnings about the experiment, hoping that the young man would still want to continue despite the risks. “You understand, Evan, that this isn’t a military trial. We’re not making super soldiers here like in those movies you mentioned in your first interview. The serum we will give you—VX-13—is designed to accelerate growth and repair at a cellular level. In theory, it should help rebuild muscle mass at an extraordinary speed. But it—”

Evan smiled, rubbing the back of his neck. “That’s exactly what I want. I’ve been trying for years, and this feels like my shot. And I know it’s not like Captain America. Don’t worry,” he wanted to sound cool, but despite the warning, he was anxiously eager to get started.

The other scientist, Dr. Muller, crossed his arms and frowned, aware that Evan wasn’t giving the implications the serious thoughts they required. “There are risks. The serum has unpredictable responses. It could make you sick. It could cause organ strain. You may grow, yes—but how much, or how fast, no one can say.”

“I know,” Evan said. “But I already signed everything and gave my consent for it. So, let’s do it!” he added, and the doctors nodded.

The two older men walked to the console and gestured for Evan to get into the chamber in the center of the room. Evan took a deep breath and stepped forward. Up close, he could hear the faint sounds coming out of the glass chamber. The transparent panels gleamed like ice, and a blue light illuminated the network of tubes that ran along the walls. Inside it, Evan saw padded restraints and metallic nodes awaiting him.

The scientists began keying in sequences as lines of code scrolled across multiple screens. Evan entered the chamber, and the glass slowly slid shut with a pneumatic hiss, sealing him within and locking the restraints around his body. The light inside softened, turning the space around him a calm shade of blue. He looked small inside the chamber, but he was used to that at this point. Everything was always larger than him, taller, and thicker.

From his control station, Dr. Carlon talked through the intercom. “We’re beginning the sequence. You already know how the protocol is. The injections will be automatic. Once the chamber seals, you’ll feel the first doses immediately. Stay calm and breathe. Remember, if you need to stop, say so.”

Evan nodded, taking a deep breath and briefly closing his eyes in preparation for what he expected to be the beginning of a new life. “Got it,” he said, already thinking about having the muscles he had always dreamed of.

He heard devices moving around him, but his mind was elsewhere, thinking about the decision that had led him to this moment. He remembered the online announcement, promising to help the subjects gain muscle mass. He didn’t hesitate to sign in, aware that he probably wasn’t fitted for such an experiment, but surprisingly, he had been chosen for it. He had no idea if he had been the only submission, but it didn’t matter anymore. His life was about to change if the serum worked as the scientists expected.

“Subject ready,” an AI voice announced aloud. “VX-13 protocol initializing. Prepare for injection cycle one.”

A mechanical click echoed inside the chamber, and small needles extended from the walls, aligning perfectly with points along Evan’s arms, chest, and thighs. He stiffened and groaned as the first shots hit, feeling the dozen needles striking in unison. He gasped as the serum flooded his veins, burning along his limbs and making his pulse quicken. His fingers clenched as the heat spread through him, and his muscles tensed under the sudden burn. His breathing quickly turned into a heavy pant, and the world around him seemed to spin.

Outside, the scientists watched as Evan’s almost nonexistent muscles flexed beneath his skin, and the first visible signs of the serum’s effect took hold. The young man chuckled and smiled despite the pain, half in disbelief and half in excitement, and his eyes widened when he felt his body pulsing. A sudden rush of energy, consuming every inch of his body, made him feel powerful for the first time in his life, even though his body hadn’t changed much. The sensation was enough, but he knew more was coming.

The scientists watched the monitors spike—heart rate up, temperature rising. Evan exhaled shakily, trying to remain calm as his muscles twitched and he could already feel something shifting inside him.

“Serum spread to 60% of the muscular tissue. Phase two, cellular restructuring initiated,” the AI announced as Evan groaned again.

Dr. Carlson frowned at the data. “That’s faster than expected. 60% should’ve taken at least 10 minutes. His body is accepting and processing the serum way too fast.”

”Keep it steady,” Dr. Muller commanded the AI, but the ”60%” had already changed to ”75%.” “Maybe we should’ve given him a smaller dose, given his initial size?” he said to his colleague, who could only stare at the numbers in disbelief.

Inside the chamber, Evan’s breathing grew heavier. Thick veins popped up along his forearms for the first time in his life as something deep inside began to stir. He felt something pulsing through his whole body, not only his heart but also in every muscle that started throbbing outward. His arms bulged and softly pushed against the chamber’s restraints that had been loose only seconds before. The sensation was intense, pleasurable, but painful.

He couldn’t move his hands anymore; every tendon felt locked in place as the slow expansion continued. He could feel the pounding of his heart against his ribs getting faster and louder, so strong that it seemed to shake his entire chest cavity. The sound echoed inside his ears like a drum, but he focused on the tingling spreading all over his body. He could feel something happening even around his crotch, as his average cock stirred.

“Injection cycle complete,” the AI said as the needles finally left his body. “The subject’s heart rate elevated but within the safe spectrum. Serum has spread to 100% of the muscular tissue. Restructuring is increasing. Muscle fiber density is exceeding predicted levels.”

“Something’s off. None of the previous twelve subjects processed the serum this fast. It is a good sign, but not within the ranges we estimated,” Dr. Muller said, reading some charts.

“We’re too far at this point to stop,” Dr. Carlson said, clearly concerned. “The failures with the twelve previous subjects won’t define what’s going to happen with this one.”

Evan suddenly groaned louder as his body jerked with an involuntary spasm. His chest heaved violently, and each breath rattled in his lungs as the expanding pressure forced his ribs outward. The structure of his torso stretched and adjusted under an intense unseen strain. Then, faint cracks and pops joined his groans as bone and muscle realigned with the force of an earthquake. The pain was immense, but Evan couldn’t help but desire more.

His shoulders drew back with an audible creak, spreading wider as tendons tensed like cables under tension. The faint outlines of his bones blurred beneath the surface as layers of new tissue formed, sliding and tightening into place. His arms convulsed, thickening in slow waves along with the rest of his body.

Evan’s throat worked around a hoarse cry—“Ngh—hah!” —half gasp, half laugh. The sound trembled as his pulse pounded in his ears.

“Doctor, readings are spiking!” Dr. Muller said, widening his eyes in concern.

“Let it run,” Dr. Carlson said, remaining calm and cold. “He’s still stable.”

Evan arched his back as the growth intensified, starting deep in his core and surging outward. The muscle along his abdomen flexed and thickened, pushing outward and settling into rock-hard density. Each breath made his torso push broader and wider as his expanding lungs pressed against his ribs. His once-narrow thighs began to press against one another, growing thicker and heavier as veins snaked along his legs. The loose shorts clung tighter by the second, and the fabric stretched audibly as the seams strained and popped sharply.

The blue glow from the chamber lights pulsed faster, briefly changing to a red hue as his body exceeded the expectations. His height increased steadily, quickly going up—five-foot-one, five-two, five-three. A groaning creak announced every new inch as his bones lengthened and adjusted to the force tearing through him. The entire chamber vibrated under the stress, and a low mechanical whistle blended with the chorus of crackling joints, stretching fibers, and the unsteady rush of his breath.

“Muscle mass is increasing rapidly. Subject height is increasing as well,” the AI reported. “Five feet four inches... five feet six... five feet ten...”

Sweat poured down Evan’s brow as he felt every inch of his body tightening, thickening, and lengthening. The sensation was enough to push his cock into full hardness, and even that body part felt different inside his straining shorts. His once 5-inch hard cock now lengthened down his leg and tented the fabric as it reached over 10 inches long and as thick as a soda can.

“It’s—it’s working!” He cried with his deeper voice, marveling at how big he already felt.

His chest continued to broaden as each pectoral rose into full slabs of muscle that twitched with each heartbeat. The valley between them was so deep already that a man’s hand could get lost there. His shoulders looked as broad as doorframes at this point. His arms flexed uncontrollably, and muscles bulged larger than his head. His spine stretched again—six-one, six-three, six-six—and the glass chamber groaned faintly as he filled the confined space.

“Doctor, he’s getting too big!” Dr. Muller said. “We should abort!”

“NO!” Evan shouted from inside. His voice had grown louder and deeper—sounding more powerful. “I can do this! It feels—amazing!”

The scientists froze, looking at Evan’s grin through the glass. His neck thickened as his traps rose and pushed against his ears. His shoulders pressed against the curved walls, and the once-loose shorts looked skin-tight and stretched to their limit. He could feel his thighs thickening, his bulge expanding, and even his ass felt rounder and meatier. He tried to look down to see if what he felt was real, but he could only see a massive wall of flesh formed by his pecs. A cocky grin immediately spread on his lips. He was close to bursting out of the chamber that had been too big for him only a few minutes ago.

“Six foot nine... six eleven... seven feet even,” the AI reported. “Warning: chamber integrity compromised.”

The metal frame groaned as a spiderweb crack split across the glass, then spread in slow motion, fracturing outward as Evan’s expanding frame pressed against every surface. The pressure inside the chamber grew unbearable, but the young man could only smile and rejoice in the sensation. His muscles flexed, pushing outward with immense power as the blue lights in the chamber turned red. Warning signs appeared on all the screens, announcing the inevitable.

His abs bulged outward, and his chest pushed forward with more mass. The vibrations of the chamber extended through the floor, making loose instruments rattle off the tables. Lights flickered overhead, momentarily leaving the room in darkness except for the red lights coming from the chamber. The sounds of the storm outside added a layer of horror to the scene as alarms erupted. The warning lights painted the lab in frantic red as the chamber bent outward, the cracks grew, and Evan’s body gained more mass.

“Doctor, he’s—he’s not stopping!” Dr. Muller said.

“Contain it!” Dr. Carlson shouted, finally aware of the dangers. “Shut it down! Start canceling protocols. Inject the antiserum.”

“Override denied. Cellular expansion continues. Subject estimated body mass: 1,400 pounds and increasing,” the AI replied coldly.

The glass shattered loudly, and shards exploded outward like a storm of crystal, scattering in all directions as the chamber burst open. A shockwave of heat and compressed air swept through the lab, knocking papers and equipment to the floor. Between the flickering lights, the red hue, and the smoke, it was almost impossible to see what was happening. But the doctors heard heavy footsteps in the center of it all, as a huge dark figure moved through the cloud, with metal and glass fragments sliding off his skin like water.

When the lights steadied above, the scientists could only stare and gasp. Evan’s body had grown beyond human proportions. Every muscle on his body bulged enormously, and the sweat glistening over his skin made him look even bigger under the lights. His shoulders were at least 7 feet broad, with each pec looking heavier than a heavyweight bodybuilder’s entire body. His arms were thicker than most men’s torsos, and his legs were too titanic to comprehend.

The fabric of his shorts, which had once fit him loosely, looked strained on his body, not only highlighting his muscular thighs and broad hips but also the immense bulge he carried at the front. Behind him, his ass had grown impossibly round and full, holding more mass in each cheek than Evan’s whole body used to have.

The seams of his shorts looked dangerously close to bursting at this point, and it only took a heavy throb of his cock to destroy what was left of his clothes. His stance widened instinctively as the last restraints of his clothing gave way. His cock and balls burst into unrestrained freedom, making him sigh with delight as his 2-foot-long cock stood tall and slapped against his abs. His balls hung low, expanding visibly now that they were free.

Evan lifted his head and laughed so loud that it sounded like a roar escaping his throat, vibrating through the wreckage and rattling the walls. The scientists stumbled back, shielding their faces from the flying debris and searing light, as he stood in the broken shell of the machine. They were conflicted between fear and pride since the experiment had worked beyond their expectations, but something didn’t feel quite right.

“More!” Evan shouted, flexing as his biceps swelled to an impossible size. “More! I can feel it—the growth’s not over! The serum is working!”

The AI’s voice continued to narrate. “Subject’s cellular multiplication is exceeding safe parameters. Muscular hypertrophy beyond the theoretical threshold. Skeletal support is compromised. We’re entering mass overdrive.”

The scientists backed away, terrified, as the floor trembled beneath Evan’s weight, and every tremor felt like a warning of the scale he had reached. The growth slowed only slightly, but without the chamber around him now, every pulse was visible and impossible to ignore. His body continued to thicken as muscle mass layered upon muscle. His size and weight forced his posture lower as they pressed against each other in immovable stacks.

The floor groaned beneath him while his chest swelled even more and his ribs spread audibly as he fought for space within his own body. Each attempt to move sent slow motions through his shoulders and arms, as joints flexed with protest under the incredible pressure. His chest had grown so wide he could barely bring his arms closer than a few inches, and the motion was sluggish and heavy as if submerged in thick liquid.

His height stabilized at last—7’2” tall—but his mass still climbed, and each new layer of size pressed down upon him, restraining his range of motion. Every other minute, he had to move his feet farther from each other to give his thighs enough space to expand. His immense lats pushed his arms away from his body, fighting against his own biceps, triceps, and pecs. His traps reached higher, engulfing his head and locking it in place. Despite this, Evan loved it.

He smirked, flexing as much as he could. “Look at me...” he shouted, making the walls shake with his voice. “I’m unstoppable now... unstoppable...”

The sensation was intoxicating, but as seconds passed, the euphoria gave way to strain. His limbs could barely bend as the immense proportions of his own frame pressed inward from every direction. His head shifted only slightly atop the thick columns of his neck and traps. The muscles along his shoulders and chest pressed so tightly together that the skin shimmered with tension. His entire frame trembled with the effort to move, like a hill trying to adjust itself through a wave of earthquakes trapped inside flesh.

The frame that had momentarily felt invincible now held him still, bound by its own enormity. His breathing had become a heavy pant as his lungs and heart fought to sustain so much mass. He had reached dangerously big proportions, but deep down, he loved it. He struggled, but his grin widened amid the effort.

“More...” he gasped through the roar of his own breath. “More mass...”

“Estimated body mass: three thousand pounds,” the AI declared. “Growth is stabilizing and slowly stopping. Mobility: negligible.”

As the minutes passed, the alarms stopped, and the only sounds left in the room were the echoes of the storm outside and Evan’s heavy breathing. He stood there, like a mountain of muscle, far too large for the human form to contain comfortably. The immense breadth of his shoulders cast shadows across the ruined lab, glistening under the lights and looking surprisingly smooth despite the insane proportions.

His chest rose and fell, pushing forward over 3 feet from his ribcage, overshadowing the top rows of his abs, and looking so heavy that his nipples pointed downward. His arms were locked in place, with biceps so enormous that they would put beach balls to shame. His legs were immense, big enough to support his weight, but too thick to move. Even his ass fought for space behind him, but looked magnificently perfect.

And to crown such a titanic body, his cock stood tall and heavy, over 4 feet long, almost 2 feet in diameter, with veins thicker than grown men’s arms adorning the length. His balls reached almost to the floor, churning and sloshing with gallons upon gallons of cum. Every inch was impossible to comprehend under human standards, and Evan could only smile even in his immobilized state.

Dr. Carlson took a hesitant step forward, conflicted between awe and horror. “What—what have we done?” he whispered, standing before the colossus who had been fragile and thin only a few minutes before.

The doctor reached up and caressed Evan’s immense pecs, feeling how the heated-up skin pulsed with each heavy breath. As he stood there, motionless and admiring their creation, Dr. Muller joined, looking pale but excited.

The AI then spoke softly: “Subject seems stable. Estimated mass: three thousand five hundred pounds. Height: seven feet two inches. Cellular activity sustained at maximum capacity. Running closing scans,” the AI added as the doctors and Evan didn’t move. Then, another warning popped up on the screens. “I found traits of the VX-13 serum on the subject system. Possible second wave of growth, unable to estimate the outcome.”

Dr. Carlson’s eyes widened as he felt Evan’s skin getting hotter. “What? Impossible!” He shouted, exchanging a scared look with his colleague as Evan laughed louder than ever, making the whole place tremble, and the alarms went off.

THE END

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PS: Hey everyone, this Halloween Special was inspired by the famous scene in Marvel's "Captain America: The First Avenger" (if you couldn't tell already). In this story, Evan wants to experience the same as Steve Rogers, but... What if things go wrong, or way too well? Anyways, ENJOY!