At his sister's house, he saw the SUV parked in the driveway. He knew it was Clint's. He had met his sister's other boyfriend, and watched as he transformed himself from a geek, to a runner, to an athlete to a bodybuilder, all in just several months. He knew that Clint and Jen had had arguments, and that Clint had refused to help Mark. That's why Jen sought out Jim.

What Mark hadn't counted on was his own burgeoning sexuality. Jen had never taken her sexual encounters seriously. They were just for fun. The guys she found, Clint, Jim and others were just toys for her amusement and to be discarded when someone better came along. Mark had always accepted that. Until now.

Jim was Mark's friend. Maybe more. No one had ever taken such an interest in him before, even if it was part of Jen's scheme. Mark was developing feelings for Jim. He hoped the feelings were reciprocated, but he wasn't sure. That didn't matter to Mark now. He knew that Jen and Clint had hurt Jim, and Mark wanted vengence for his friend.

Mark walked over to Clint's SUV. As hard as he could, he stabbed the knife into the front tire. Nothing. He did it again, and heard a faint hiss as the air began to escape. He was about to leave, but noticed that the vehicle was unlocked. He smiled. He opened the back and searched. He found the car's jack and grabbed it. He'd dispose of that on the way home. Running the knife against the SUV's paint was his final gift to Clint. He ran back to Jim's. No one would ever know it had been him.

Inside the house, Jen balanced on top of Clint's massive form. She cried in pleasure as she rode Clint, feeling every inch of the man's power. He licked her breasts as his legs lifted her, bucking wildly in time to her thrusts. Her mind was filled with erotic pleasures as Clint exerted his power over her. He might be her playtoy, but she was his as well.

Clint's mind was filled with his own power and his own manliness. He revelled in the day's events, comparing his form to Jim's and quashing the other man's powerful form with his own. He recalled Jen's reaction as she compared their bodies with her touch -- the way she had been drawn to Clint's power and had shunned Jim's. He thought of Jim struggling to display his own manliness, his muscles flexing hard and huge only to be made small with the display of Clint's extreme muscle. Clint relived the rush of lifting more weight than any man had ever lifted before, and the feeling of his muscles growing and swelling with power. In his mind, he was a super hero, a man's man capable of having any woman and dominating any man.

Clint felt his orgasm building as Jen ground her body into his groin. He reached for her breasts as a way of feeling his own pecs. Rubbing their nipples together was a ploy to feel how much bigger and harder his chest was than her ample endowment. He rubbed his hand along his abs, feeling the depth between the rocky muscles as he went to rub her clit. He felt the thickness and power in his legs as he thrust harder, trying to conceive the extent of his growing power. He fantasized about his increasing strength, thickening muscle and imagined the jealousy of other muscle men as they found themselves unable to compete against him.

He felt his juices flowing as Jen orgasmed. Her screams of "Clint!", "So hard!", "So strong.", "Fuck me hard!", and "Fucking hulking beast!" only fueled his fantasy of his own power. He told her to feel his muscle, feel his power and her fingers desperately tried to dig into his invulnerable body. Clint flexed and erupted into her for the fifth time that night.

Jen collapsed next to him, out of breath from the experience. Clint felt her hands on his body, gaging the size and power that was his. She moved to snuggle against him, her small body against his massive one. Clint was ready to go again, but he didn't think Jen could handle another round. He'd have to wait for morning.

Jen and Clint finally got out of bed shortly before noon. The night has been full of sex interspersed with short naps. "You're a fucking machine," Jen had teased.

"It just keeps getting better and better," Clint agreed, pulling up his briefs as he began to dress.

"I know a way it can get better," she said.

"Ya, like how?" Clint asked, confident in his superiority in every way.

"Jim's got a secret," she said, secretly knowing that the experience last night could have been better. She had chosen Clint, but that didn't mean she had to settle for something less. She'd make her own fantastic muscle lover.

"That wimp. You saw what a gnat he is compared to me," Clint huffed back.

"Oh, you got the muscle, that's for sure," she said, coming to him and stroking his chest. "But he's got the dick."

Clint looked at. No one had ever questioned his horse cock before, nor said someone was better.

Jen recounted the story, of Jim's formula and his total control of Mr. Fantastic. When she told him how she had stolen his formula for Jim, she could see Clint's anger rising. "But babe, it's ok. I chose you," she tried to reassure him.

"Then maybe you could steal that little formula for me too, bitch," he replied.

"I don't think he'd trust me after yesterday," she said, backing away, afraid of what Clint might do.

Clint didn't move. He seemed deep in thought, then grinned. "It's OK, I'll forgive you, this time." The tone of Clint's voice made it clear. If Jen ever betrayed him again, she'd pay for it. "I'm sure there are other ways to find that formula." Clint tensed his arm, causing his bicep to ripple into a mighty peak. He moved his hand to his crotch and grabbed it, imagining how much bigger it, and his muscles, could become. •