Verminator

Verminator is a supervillain in Bionic Bunny. His main weapon is his sharp claws, which he uses to create a painful, high-pitched noise by scraping them on a chalkboard.

His first appearance was in Arthur's dream in the episode "Arthur's Underwear" (although this was really Mr. Ratburn). He tortured Arthur's classmates with the nails on chalkboard sound until Arthur (as Bionic  Bunny) burst into his lair. Instead of being intimidated by the hero, Verminator burst into laughter because Arthur had forgotten to wear pants.

Action figures of him are also seen in the intro of "Clarissa is Cracked".

Trivia

 * His name is a play on ', but his costume bears no resemblance to the character. His appearance could possibly be based on ', from Teenage Mutant Ninja Turtles, or a  operative from G.I. Joe.