Janitor Bob Taggart was a junky and liked nothing more than to shoot up whatever drug he could find. So when he was emptying the waste bin and saw a needle still half full in the bin, he thought why the hell not? He wasn't afraid of infections.
The first thing he noticed was it definitely was not heroin. The second was he had a raging erection. Maybe it was some new trial ED concoction. He grinned at the idea, opiates wasn't great on the libido, and he hadn't had a good wank in ages.
He locked the lab door and pulled the professor's swivel chair into a corner away from the door and windows.
Then groaned as he collapsed in the chair and spread his legs wide as he let down his fly freeing his swollen cock to burst out. He stared in shock at the huge manmeat in his lap. This was not some ED cure, his cock was definitely bigger and veiny, and dark and the foreskin was returning. It stretched up past his bellybutton. If it weren't so thick he might be able to bend down and suck himself off.
He started jerking, running both his hands up and down the shaft, he needed them both for the behemoth between his legs.
He grabbed his balls and noticed they felt swollen too, and huge like lemons.
He had to spread his legs further, they were swelling, maybe this was some hallucinogen, as he ran a hand up his body he could swear he felt chiseled cut abs and huge muscular thick pecs coated with silky smooth hair.
Then he came, and it sputtered and splashed his chest soaking through his shirt. His spasming cock jerked hard again in a second blinding torrent of pleasure and his cum splashed his face. He licked his lips and tasted his sweet cum. Only fags did that, and he wasn't no fag. Except it tasted really good, and he wondered what other men tasted like, what it felt like having a jaw cracking cock in his mouth. And his cock spasmed a third time with its largest load yet, as he moaned and groaned pumping his dick with both hands and aiming for his mouth as he bent over, his surprisingly limber body lets his lips brush the tip of his dick. He drank down his seed as his biceps grew and tore his sleeves to shreds.
He tore them off and grinned at the huge black arms he now sported. "Hello daddy," he grunted his voice low and gravely like a beast.
His dick immediately hardened again at the sound of his voice.
Bob spent over two hours in the lab jerking and cumming as he reveled in his new beastly body.
When he was done, he mopped up and swaggered about with the rest of his work in sweat pants that strained to contain him and in an equally strained shirt.