Fear
On the Halloween episode of Saturday Night Live in 1981, the California punk band Fear decided to do something different. They enlisted a group of slam dancers to mosh in front of the stage while they performed (including actor and SNL alum John Belushi, who had gotten the gig for the group). Things quickly spiraled out of control, and the set had been damaged to the tune of $20,000 to $40,000 by the end of their performance. Fear was never allowed to return to the show.
Milton Berle
Milton Berle had already established himself as a television legend by 1979. That didn’t make the cast and crew of Saturday Night Live like him anymore. Berle’s improvised monologues, musical performance, and pre-planned standing ovation irritated those on the show, particularly Lorne Michaels, who banned Berle and banned the episode from syndication for over 20 years.