Nate had always been the kind to laugh last. Sharp green eyes, a rebellious lock of hair that seemed to challenge everyone, and an aura of “nothing can touch me.” At the end-of-semester party in Marcus’s loft, the beer flowed and the atmosphere was full of jokes and reckless energy.

Marcus, a genetic engineering student, had brought a curious object: a sleek glass syringe filled with a glowing blue liquid. “A serum that alters endocrine tissues in real-time,” he said, laughing. “I developed it for my thesis. But it has... unexpected side effects.”

“One injection and your body changes,” he explained with a grin. “It only lasts a few hours.”

The others laughed, but Nate — with that typical arrogance — laughed louder. “Inject me. I bet nothing happens.”

Applause erupted as Marcus plunged the needle into Nate’s arm. It took just a minute. Nate stiffened, then arched backward, groaning. Before their shocked eyes, his chest began to swell.

Not just a little.

His pecs exploded beneath his white tank top, transforming into two massive, heavy, perfect breasts.

The room fell silent. Then the quiet was broken by slow, deliberate clapping.

“Nate…” Marcus grinned. “I think you’ve won… something.”

Nate panted. His body was still that of a guy, but his chest — huge, sensual, surreal — turned him into a hypnotic attraction.

“I… feel weird,” he murmured, as everyone stared, aroused, unable to look away.

And that night, under the hungry eyes of his friends, Nate became the center of every desire. With a cheeky grin, he began to swing his new massive tits back and forth, provoking laughter, cheers, and applause. He laughed too, amused by the grotesque and irresistible body he now flaunted shamelessly. Every joke, every game, every fantasy revolved around his exaggerated chest, which seemed to have a life of its own.

And for the first time, Nate wasn’t the one laughing last.