There was an episode where the school's wrestling team was being cut down one by one in very odd ways. Two memorable ones were Death by Vibrating Bed and the Reverse Hand Drier, which sucked the wrestler up into the little foot and a half square box.
The Garbageman is probably one of the creepiest villains ever.
"Endless" Mike Hellstrom in certain episodes, but especially in "Pinned!". All of it. He caused a kid got SUCKED INTO A HAND DRIER. "They say there are 106 bones in the human body...where to begin, where to begin..."
Mike's obsession with Big Pete. When he didn't qualify to wrestle him because he was a couple of pounds over his weight class, what does he do? He pulls out his own teeth with a pair of pliers to make the grade.
"I was thinking about your character and, y'know, the bully character is such a cliché, and how you found a way to make it someone that really resonates. I was thinking, "what makes Endless Mike so special? Why is he so different from other bullies?" And I was actually thinking of "Pinned!" and I was like "oh yeah, that's right, we had him murder people in the show!" So, yeah — that's a big — you don't usually see bullies murdering people — or extracting their own organs to make weight."