Homer attends a nuclear power convention with Lenny and Carl, but when he returns separately and stops eating pork chops and drinking beer, Lisa thinks that he has been brainwashed by terrorists who want him to destroy the nuclear plant. Guest stars include Kevin Michael Richardson and Kristen Wiig.
The twenty-fourth annual Simpsons Halloween episode features an opening directed by Guillermo del Toro and the following segments:
"Oh, the Places You'll D'oh!": In this twisted parody of Dr. Seuss's children's books, Homer abducts Bart, Lisa, and Maggie and rides around Springfield wreaking havoc as "The Fat in the Hat".
"Dead and Shoulders": In this parody of The Thing with Two Heads, after Bart is decapitated during a kite accident, his head is attached to Lisa's body and the two must live together as one -- until Bart discovers that he can fully function whenever Lisa is asleep, and sets out to incapacitate her so he can have her body.
"Freaks, No Geeks": In this parody to the 1932 horror film, Freaks, Homer and Marge are circus performers (a strong man and a trapeze artist respectively) with Burnsum and Bailey, and Homer has a plan to marry Marge off to a circus freak (Moe) so he can rob him of an emerald ring.
A death in Springfield leads four characters to look back at moments they now regret; Homer selling stock to buy a bowling ball, Marge for listening to too much Kiss music while pregnant with Bart, Mr. Burns breaking up with a French woman, and Kent Brockman not following Rachel Maddow from local news to cable. This episode guest stars Rachel Maddow and Joe Namath.
Marge invites an old pen pal to stay with Homer and cross items off his "to-do" list from when he was 10 years old, so that Homer can embrace his "You-Only-Live-Once" spirit. Meanwhile, Lisa starts an honor code for the school to combat cheating. Jon Lovitz voices Llewellyn Sinclair.
Homer delivers a baby in an elevator in Carl's apartment building, and becomes attached to "Homer Jr." - a little too attached; Lisa tries to unionize the Springfield Atoms' cheerleaders. Elisabeth Moss guest stars as Gretchen.
Lisa's opponent for the second grade representative on the school student council is her new best friend - and a Republican that the town's party officials want to get elected at any cost. This episode guest stars Anderson Cooper, Maurice LaMarche, and Eva Longoria.
Bart becomes a model student when Principal Skinner offers a ride in a submarine as a reward to the best behaved kids, but when Skinner leaves Bart behind, Bart gets even; Krusty sells the rights to create foreign Krusty shows (for a 75% cut), only to find out that the other Krustys are doing better than he is. Kevin Michael Richardson guest stars.
Springfield becomes a tourist hotspot after an accident involving the nuclear plant and the Springfield tire fire causes snow to fall for the first time in a long time -- and when Springfield's stores raise their prices, Marge turns their house into a bed and breakfast for the out-of-towners.
Homer's problems with movie theaters lead him to start downloading current movies illegally so he can watch them at home, but when Marge sends a check to Hollywood to pay for watching a movie Homer pirated and she watched, the FBI arrest Homer.
Guest stars in this episode include Judd Apatow, Will Arnett, Rob Halford, Leslie Mann, Kevin Michael Richardson, Seth Rogen, Paul Rudd, and Channing Tatum.
The Comic Book Guy falls for a Japanese manga artist, but Homer's advice and the woman's father may ruin his chances at true love. This episode guest stars Harlan Ellison, Maurice LaMarche, and Stan Lee.
Mr. Burns gives his workers Google Glass-style computer glasses so he can spy on them, but Homer gives the glasses to Marge, and discovers that Marge has been going to therapy to discuss her life. Meanwhile, Nelson bullies Bart into giving him the best Valentine's Day gift ever. Guest stars include Maurice LaMarche and Will Lyman.
Bart makes friends with a transfer student named Diggs, an expert in falconry who saves Bart from the wrath of the Springfield Elementary bullies – and who intends to take to the sky himself, which makes Bart worry about Diggs' sanity. Daniel Radcliffe guest stars.
Lisa discovers that Sideshow Bob has become the chief scientist of a massive chemical engineering company, but the two of them bond over their appreciation for high-culture. Meanwhile, Marge ends up a church volunteer to help horny teenagers become abstinent. Kelsey Grammer guest stars.
Grampa, Jasper, and the Crazy Old Man move in with the Simpsons, causing Homer to take to the elderly lifestyle; when Bart stands up for Nelson after he's caught wearing his mother's underpants, Bart becomes an honorary bully, only to end up taking the fall at a gathering of bullies when their leader is hit by a slingshot. Kevin Michael Richardson guest stars.
Homer is recruited as a World Cup referee after Lisa extols his integrity on the youth soccer field in a Springfield Elementary speech contest. But when the Simpsons travel to Brazil (again), Homer finds his honesty tested by one of South America's slickest gangsters in the soccer match-bribing business. Andrés Cantor guest stars.
Marge thinks that Lisa is dating below her standards when she brings home a competitive eater-in-training named Lucas Bortner, so she enlists Homer to help Lisa explore other options. Meanwhile, Bart receives gifts from Snake Jailbird for helping him get out of a jam, but when a betrayal from Milhouse sends Snake back to prison, Bart hatches a plan to get him out. This episode guest stars Zach Galifianakis.
Homer dies, but Professor Frink manages to replace him with a clone...and another...and another...which leads to the future of "Future-Drama", where Homer ends up as a screen saver, Milhouse turns into a zombie (and his wife, Lisa, seems to like him better that way), and Bart still has ex-wife problems. Amy Poehler guest stars.
Bart makes a voodoo doll of his hippie art teacher when he gets sick of art class and cast a spell to make her sick, but when he inadvertently gets her pregnant, he becomes a savior to Springfield couples trying to conceive - and is subsequently kidnapped to help conceive a thoroughbred race horse. Guest stars in this episode include Tavi Gevinson and Joe Mantegna.
Homer wakes up to a world made out of LEGO bricks and grows to like this new world, where everything fits in and no one gets hurt — until he begins seeing flashes of a previous life and, with help from the Comic Book Guy, discovers how he ended up in the LEGO world.
After Homer ruins a game night at the new neighbors' home, Marge decides they're better off not having friends, but she's not about to let Lisa share the same fate. This episode guest stars Carl Kasell, John Oliver, and Peter Sagal.
Bart feels guilty after he wins the annual "last day of school" race around Springfield Elementary School, with help from Nelson, who beats up the frontrunner, Milhouse. Meanwhile, Homer tries to bring back 4th of July fireworks after they are canceled due to budget cuts. Glenn Close and Edwin Moses guest star.