The Simpsons Season 21 Episode 22
The Bob Next Door
Bart becomes convinced that his new neighbor, Walt, is his archenemy, Sideshow Bob, disguised and back for revenge. But when Marge tries to convince Bart otherwise by taking him to visit the state penitentiary, a disturbing truth is revealed.
Guest Stars
Kelsey Grammer
Sideshow Bob (voice)
Pamela Hayden
Milhouse (voice)