Sideshow Bob
"Black Widower" was the second episode Kelsey Grammer guest starred in as the voice of Sideshow Bob. He had previously appeared in the season one episode "Krusty Gets Busted", in which Bart gets Bob sentenced to jail for framing Krusty for armed robbery. Grammer initially expected to voice Bob in a one-time role, but the character was amazing enough to have him brought back. Sideshow Bob eventually became one of the most popular roles Grammer ever played, and Bob became a recurring character on the show. Grammer bases his Bob voice on theatre actor and director Ellis Rabb. He had once worked for Rabb, whose "lamenting tones became [the] foundation for Sideshow Bob".