Mad Dog (puppet)

From Muppet Wiki

Mad Dog is the burly but stupid henchman to Bugsy Them in Dog City. He is unable to resist obeying such commands as "sit" and "stay", thanks to spending two (I mean fourteen) years in obedience school.

In the later spinoff series, there was a different Mad Dog, who served as henchman to Bugsy Vile. The original Mad Dog puppet was recycled as Bowser for the Muppet framing sequences. Prior to that, however, Mad Dog was amongst the dogs in the pet detention center in The Muppets at Walt Disney World.