Riff Raff: A Handyman
Played by Richard O'Brien in both the original play and the film, reprising the role at the Belasco. Richard said once that if you play the part right, it twists you a little bit. Sorry to spoil it for you, virgins, but this Igor gone bad is just one more example of the butler did it.
From the 1984 Audience Participation poster (text by Sal Piro):
"A servant, he wears Goodwill rejects, tails and spats. No tie.
Displays an unnatural interest in his sister. Has ambitions of becoming the master. "Sing to us, oh Hairless One!" (Go ahead, take the plunge. Shave your head.) "