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.
- Directed by
- Nancy Kruse
- Written by
- John Frink
Guest stars
All episodes — Season 21
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S21 E1Homer the Whopper
Sep 27, 20096.922 min
Homer gets the lead in a movie about a superhero who can take on the powers of every superhero in any comic book he touches. To whip Homer into superhero shape, the studio hires a celebrity fitness trainer.
S21 E2Bart Gets a 'Z'
Oct 4, 20096.323 min
The fourth grade students of Springfield Elementary School decide to spike Ms. Krabappel's coffee in order to teach her a lesson after she takes away their cell phones. She is fired by Principal Skinner, who hires a new teacher named Zachar
S21 E3The Great Wife Hope
Oct 11, 20096.322 min
The men and boys in Springfield become obsessed with Ultimate Punch Kick and Choke Championships, a violent sport where fighters inflict severe pain on each other. When Marge and her friends stage a protest against the sport, the show's pro
S21 E4Treehouse of Horror XX
Oct 18, 20096.923 min
Dial "M" for Murder or Press "#" to Return to Main Menu- Lisa is forced into a Hitchcockian murder scheme by Bart. Don't Have a Cow, Mankind- Springfield is once again overrun by zombies, thanks to Krusty Burger's latest sandwich. There's
S21 E5The Devil Wears Nada
Nov 15, 20096.423 min
Marge and a group called the "Charity Chicks" pose for a calendar in hopes of raising money for charity, but Marge becomes the talk of the town thanks to her racy poses. Meanwhile, Carl is chosen as the newest supervisor at the nuclear powe
S21 E6Pranks and Greens
Nov 22, 20096.122 min
Principal Skinner is getting fed up with Bart's pranks, so he informs Bart that he is not the best prankster after all. A former student named Andy Hamilton is hailed as the best prankster, and Bart sets out on a mission to track Andy down.