Like the hotel and the rest of the neighborhood, the gym was exceptionally seedy. Its floors were bare cement and the equipment was so old, so primitive that it was actually made of iron and steel. But the scent of the place -- mold with a twist of sweat -- was erotic, and Leonard thought that since it was almost empty it would be easier for him to experiment with his new strength.

It was the kind of gym that no one cared what you wore – just what you could lift. That was perfect. Leonard didn't have workout clothes. He just wore an extraordinarily strained pair of ordinary pants and street shoes. He shed his shirt and dropped it in a corner on the floor.

Leonard picked up the bulkiest pair of dumbbells he could find on the rack and curled them. He could tell they weighed something, but lifting them was no effort at all. One hundred kilos a piece and they weren't even a challenge. The only thing hard about the set was his prick, which enjoyed the tremendous feeling of power at elevating the dumbbells to his chin and the pulsing of blood through his body. The veins in his arms were filling, raising and twisting like snakes over his smooth, hard muscles as he squeezed his arms.

Across the room through the mirror he could see an admirer, an Uzikan, one of the near-system alien races that visited Earth occasionally, now that the government had liberalized off-world trading. Besides their natural strength and mass, Uzikans were known for their fantastic healing abilities. An Uzikan could recover from a near fatal wound in minutes. Leonard wasn't sure he could accurately read Uzikan facial expressions, but he thought the alien looked impressed with his strength and maybe a little miffed that a mere human appeared to be in his league.

Leonard loaded up an old-fashioned weight bar at the bench press. The bar could have held more, but Leonard stopped loading it at 400 kilos. The Uzikan stared. Leonard lay down on the bench, extended his arms and lifted the bar from the stand. He grinned as he lowered the bar to the edge of his protruding chest. It was as easy as curling the dumbbells. Just for kicks he finished a set of sixteen, then loaded the bar to its capacity. Leonard had to borrow 50 kilo plates from all around the gym, giving the Uzikan plenty of opportunity to stare. The bar now weighed 720 kilos.

Leonard licked his lips and wrung his hands as he sat down on the bench. This time the lift was an effort, but not a real challenge. He pushed out twelve reps and set the weight back down – mildly flushed.

The Uzikan was standing nearby now, working his arms with dumbbells where Leonard had been a few minutes ago. Leonard watched him strain with a pair of fifties. He worked to failure, set the weights down, and tensed his arms admiring the pump.

Then it was Leonard's turn to be amazed. Right before his eyes he saw the Uzikan's arms swell. The Uzikan flexed a double-bi and grinned. He picked up a pair of sixties and curled an equal number of reps with the heavier weight. As soon as he set the weights down, his arms swelled again.

The Uzikans' healing ability extended to muscular recovery -- GROWTH!

From the corner of his eye the Uzikan watched Leonard's reaction – the open mouth, wide eyes and throbbing cock tugging at the legging of his pants. Leonard thought if he wasn't careful it might tear free! The Uzikan worked his way up the rack until he finished his final set with the hundred kilo dumbbells Leonard had used. Then he moved to the squat rack and repeated the performance.

Leonard was dizzy with desire. The sight of the humanoid growing more and more muscular right in front of him -- to almost impossible proportions -- had Leonard squirting pre-cum like a leaky pipe. His nipples stood out like tiny fingers and Leonard thought he could feel them wiggling. His pounding prick stretched the crotch of his pants like an iron poker. Finally the fabric gave. His prick tore free and climbed up past his stomach. Leonard felt wetness on his chin. He was drooling!

The Uzikan was posing in front of the mirror now, admiring a physique that had become Leonard's equal in every way, but his eyes strayed in Leonard's direction, obviously aware of the effect his transformation was having.

All Uzikans were male. Uzikans wrestled before they mated. The winner impregnated the loser by forcing his genetic material into his body. The impregnated Uzikan hosted the material as it grew to gestation and burst free. An Uzikan could survive giving birth because of their healing abilities – other species, maybe not.

The Uzikan tugged down the front of his workout trunks. At first Leonard thought he was just displaying his severely striated abs, but he tugged lower, lower, until his sexual equipment tumbled out for Leonard to see. His penis was in the same league as Leonard's too. The Uzikan grinned at him through the mirror, then turned toward him. The waistband of his trunks slipped up behind his equipment as it started to swell and stretch.

Leonard stood. He knew nothing about how Uzikans wrestled, but he knew that as much as the Uzikan had grown, he had only grown to the limits of the equipment in this gym. Leonard knew he exceeded those limits. He was still stronger and so horny that he would tackle a T- Rex if it meant he'd get laid.

The Uzikan extended an upraised arm. Leonard mirrored his action. The Uzikan's hand gripped his and began to twist Leonard's arm backwards. Leonard pushed back. His arm held fast. The Uzikan began to sweat. He bared his sharply pointed teeth. As he threw all his strength into the struggle, his whole body began to grow thicker and stronger. His skin grew so taut it seemed to dissolve. Leonard could see striations on striations, and his prick began to squirt pre-cum again as waves of desire flooded his body. But instead of getting weak in the knees, he became more determined. He was going to fuck this arrogant alien asshole into next week. Slowly Leonard's arm began to push the Uzikan's fractionally backward. The Uzikan grimaced and broke off the grip.

It wasn't over yet. The Uzikan dropped the knuckles of one hand to the floor like a football player. Leonard mimicked. The Uzikan shouted something unintelligibly alien and charged. Their arms and shoulders locked. The Uzikan drove hard. If Leonard gave an inch, he knew he'd fall on his back. But as big as the Uzikan was now, Leonard was still much stronger. It took barely more effort than standing to hold him back.

Leonard pushed harder. The Uzikan slipped an inch and dug in. Leonard wrapped his arms around the alien and doubled his efforts. The Uzikan began to quiver. His back muscles, shoulders and arms began to get thicker, swelling right under Leonard's vice grip. Bigger, bigger – until his muscles looked too large to be held by his frame. His arms were larger Leonard's legs. His legs were as thick as Leonard's chest, but still Leonard's artificially engineered body was stronger. Leonard pressed harder. The alien fell back a step and fell backward to the floor with Leonard on top of him.

A sinewy sandwich, they thrust and squirmed. Leonard had won the battle, but claiming the spoils was also a struggle. He raised one of the Uzikan's thighs, pinning his back on the ground and allowing him to examine the orifice he was taking. He stick in a finger. It was syrupy wet. He slid in several more. The Uzikan quivered. It was clear that no matter who ended up on top in the Uzikan mating ritual, both parties were winners.

Leonard bucked and fucked. The Uzikan began to work with him. Their bodies slid into each other. If Leonard slowed, the Uzikan coaxed him to fuck faster. The Uzikan's insides were just as enthusiastic. Leonard could feel hundreds of tiny tendrils pulling at his penis, tickling it and teasing it, keeping him at the peak of his arousal, the edge of release, but denying him ultimate pleasure no matter how desperately he fought for it. He felt more and more cum building inside of his balls, like the Uzikan's body was drawing it up inside of him, maximizing his load to ensure a fertile union of their bodies. He could have come three or four times with the cum he felt inside him – great gushing orgasms that would have filled buckets. Yet part of him relished the immensity of the pleasure his felt along his gargantuan prick as it slithered and poked inside of this impossibly hulked-out alien.

When the fluid inside him finally burst free, there were no words to describe the intensity of feeling that racked his entire body. As much as he came, the Uzikan's insides absorbed all of it. And when he was finished, he found he was unable to pull himself free. The Uzikan's body still milked him, sucking every last drop of seminal fluid from his thick hose, and tickling his entire prick, inside and out – almost enough to make it hard all over again.

It was almost an hour later when he was released. Leonard pulled himself off the Uzikan and free of his tight hole. The Uzikan rose. The two of them were pulling on their shorts just as someone else entered the gym. Leonard checked the Uzikan out. He snarled just as much as when he'd first seen him. Leonard chuckled privately. Only know, ten months from now, the two of them would be daddies. •