It was Vinnie.
"We're getting Ryan outta here," said Carter, holding Ryan the jockstrap over his head.
"Come on dude," Horst said to Vinnie. "Change him back. This isn't funny anymore. Do you have any idea what could have happened to him, throwing him in the lost and found?"
Vinnie sighed. "I'm sorry guys. I didn't think--I just...I just wanted to punish Ryan. For being such a jerk to me all the time."
"DUDE! He could have wound up here in storage for YEARS!" shouted Horst.
"Don't yell at me," whimpered Vinnie, pathetically.
"You can't just turn people into effing UNDERWEAR and leave them lying around the school!" Horst continued. "Do you have any idea what kind of sickos are here? If they found out Ryan Standish had been turned into this jockstrap there's no telling what they'd do with him!"
"I'm SORRY, okay?" said Vinnie. "I don't even know how I turned him into a jockstrap in the first place! I want to FIX this!"
"You'd BETTER fix this!" bellowed Carter, not wanting to be left out. He reached down with a massive hand and grabbed Vinnie by his shirt and yanked him off the ground.
"Put me down!"
"NO!" barked Carter. "Not until you you change Ryan BACK!"
"Carter..." said Horst carefully. "Carter...maybe you shouldn't..."
"CHANGE RYAN BACK!"