Bugs Bunny is a well-known cartoon character from Warner Bros., mostly through his appearances in the Looney Tunes series. He appeared alongside Michelangelo in Cartoon All-Stars To The Rescue.
In the Tales of the Teenage Mutant Ninja Turtles episode "Osoroshi no Tabi", when Usagi Yojimbo takes a bite out of a carrot, Raphael chuckles to himself and says Bugs' catchphrase "What's up, Doc?"