This was originally written to go along with a gif that unfortunately didn't make it through the Great Filter event on Tumblr. Here's a still-shot but it doesn't do it justice.

Gif was found by a fellow Redditor, available here.

Muscle Theft, Muscle Drain, Muscle Growth, Humiliation, Revenge, Role Reversal

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More Than A Grunt, by whosbiggernow

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Colton took a deep breath as he staredup at the man towering over him. He had gotten himself into this mess on purpose, but now doubt over his plan started to sneak into the edges of his mind. Hank was huge, and if Colton's plan failed he was probably going to be in for a world of hurt. Or worse, scorned and ridiculed by the rest of the barracks.

"Come on shrimpy! Prove to us that you can at least do a pull-up," Hank barked at him. "I don't know why they even let you onto the base, what the fuck good is a pre-pubescent body like that going to do in combat?" The fact of the matter was that Hank, "Hank the Tank" as most of the other meat heads in the group called him, was absolutely right. If it hadn't been for his extremely high aptitude placement Colton was certain he wouldn't have been admitted.

But that aptitude was why Colton hadn't only just been admitted: The recruiter had asked him back for a second meeting where a couple of MIBs had sat him down and told him about the need for individuals like himself in a science program the Army was running.

"No combat duties?" He had asked, half with disappointment but also with relief. "We'll see" is all they had said.

That was about two months ago, and since his induction to boot camp things had gotten progressively worse every day. Being a part of the special program, he was often separated from the other men in his group for hours a day. He wouldn't have cared, the group was mostly a bunch of meat-head killers that he had little in common with, but what would have been an already difficult task to make friends was compounded by his scientific service. Today that was going to change though. Tables would be turned. At least so long as the serum worked.

Colton could still feel the cream on his hands, the slickness of the oil-based compound giving them a slightly cooled effect. "I don't see a bar," he said meekly, egging the Tank on. He said a silent prayer when the muscleman reacted predictably and clasped his hands in front of him. Cell phones came out to film what was sure to be a humiliating activity as Colton lined himself up in front of Hank.

"You better be able to do a pull-up," called out one of the other grunts as Colton placed his hands on top of the fist that Hank was making. Standing there in front of Colton, nearly a foot and a half taller and with the sleeves of his fatigues fitted nicely around his biceps, Tank was truly living up to his nickname. A mild warmth spread from Colton's hands and into his arms, and he smiled as he completed his first pull-up with Tank acting as both bar and counterbalance.

He didn't think he could have completed even one, but the serum was giving him strength and Colton reveled in the excitement of it. The sensation drove him towards a second rep, and then another. By the fourth pull-up, he felt his boots tap on the floor. Colton figured he was losing his grip and readjusted it. He stared up into Hank's eyes, most of the man's expression hidden behind dark glasses.

But Colton saw a flash of something on his fifth pull-up: A flicker of surprise and shock on Hank's face. It was then with the sixth pull-up that things really started to fall apart.

"Dude, what the fuck?" one of the other grunts said, clearly alarmed, but Hank didn't pay any attention to him.

"Yeah!" The Tank said with a low growl, letting go of his hands while Colton dropped to the floor. Except he didn't have far to drop. Whereas Colton would have struggled to be eye-level with Hank's chest before, even with his boots on, now as the two men stood face to face Hank realized he couldn't quite see over Colton's head. And the room, at least to Hank, suddenly seemed a bit... larger? For the majority of Hank's life he had been looking over people, but now as he looked around the room of grunts he seemed to be looking up!

While frightening for Hank, the changes were overwhelmingly delightful for Colton. The serum had been designed for hand-to-hand combat, for situations such as this that were decidedly lopsided. And it was working like a charm. Once contact was made, the changes would continue until the serum was brought into contact with itself: Such as the user clapping his hands together or praying. It didn't matter if the engagement itself was broken off. In fact, that was the intention and the appeal of such a serum, as to provide as much benefit as possible for the user and be as devastating as possible for the enemy combatant.

Colton watched in near-ecstasy as the man in front of him became eye-level, the fatigues that had clung to his muscled frame beginning to look loose and baggy. The shirt, which Hank had left the top few buttons undone on to show off his hairy, sculpted chest, began to collapse in on itself as its occupant became at least a size to small for it. A gasp turned into a whimper as Hank felt his rolled cuffs slide down his biceps, the fabric no longer stretched taught over the dwindling muscles of his upper arms.

"What? How?" He said in a voice that was now an octave higher as he looked up into Colton's eyes.

A loud clank jarred him from his terror only to throw him deep into embarrassment as Hank realized his pants and belt had completely fallen off his reduced waist. A draft below made Hank acutely aware that this muscles weren't the only things that were shrinking. Once proud to strut his large flaccid cock around the locker room, the sway of meat across his groin was conspicuously lacking as Hank reached to cover himself.

Amazed at the process taking place in front of him, Colton hadn't realized how much his own body was changing too. It was only supposed to be a tool to subdue the enemy. But one of the researchers must have been working on some adaptations. Although it wasn't a part of his plan, Colton found his own body changing too.

His boots, easily four sizes smaller than anyone else's in the unit, were becoming painfully tight on his feet. And his belt was dreadfully strained around his waist as well. He bent over to untie his laces and felt a touch of vertigo. There was no way the floor could be that far away!

Glancing around the room at the other grunts, their mouths agape, Colton noticed that not only did the room itself seem smaller but the men were much less intimidating. He felt a pinch in his groin suddenly and without hesitation pulled at the belt buckle. It burst, the metal nearly knocking the phone out of one of Hank's friend's hands as it popped off. He was still recording the spectacle and hardly flinched when the projectile nearly clipped his hand, he was so captivated.

As Colton began pulling at his boots and his pants, the previously baggy shirt gave up its battle with his increased size and tore at the shoulders. He pulled it off, marveling at the difficulty of the effort because his arms and chest had swelled with so much muscle. And so, with his clothes shredded and discarded, Colton stood three-quarters naked in the middle of the room. Only a pair of silkies, stretched to the max between the massive quads and improved equipment, were left to protect Colton's modesty.

Not that he cared about modesty in the least now: Nearly a complete inversion had taken place. While the old Tank had certainly lived up to his nickname, the new Colton dwarfed the former muscle stud in every aspect. He stood head and shoulders above every other man in the room. And easily outweighed the largest of them by about 50 pounds as well.

Colton looked down at Hank, his new body casting an imposing shadow over the sniveling man. Whether the sniveling was from shock or fear; Colton didn't really care. Before things could progress any further, he brought his hands together, the serum's effects being stopped with the contact. But he held them that way, a smirk creeping across his new, wider face.

"Come on shrimpy," his deepened voice growled with contempt for his former tormentor, "prove to us you can at least still do a pull-up."