Fear
On SNL’s 1981 Halloween show, California punk band Fear decided to try something new. They engaged a group of slam dancers (including actor and SNL alum John Belushi, who obtained the gig for the group) to mosh in front of the stage while they performed. Things quickly escalated, and by the end of their performance, the set had been damaged to the tune of $20,000 to $40,000. 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 any less fond of him. Berle’s ad libs, musical performance, and pre-planned standing ovation irritated those on the program, particularly Lorne Michaels, who banned Berle and refused to let the episode to air for nearly 20 years.