4 Treehouse of Horror XXV

The episode opens with Kang and Kodos narrating a Johnny Carson-style opening (complete with clips from classic Treehouse episodes). All of the celebrity guests announced have been killed and displayed to spell the episode's title.

Principal Skinner has put Bart in detention. While dusting a desk, he finds an Aramaic inscription. Lisa uses an app to translate it which transports the pair to Hell, which is a school. Bart excels in the diabolical subjects and asks his parents if he can study there permanently. For his final test, he must torture Homer; despite Bart's hesitation, Homer lets him. A disfigured Homer proudly watches Bart graduate from Hell school as valedictorian.

Moe has a Clockwork Orange-style gang in London along with Lenny, Carl and Homer. Homer falls for a girl (Marge) who convinces him to quit and the gang falls apart. Years later, Moe is attacked at home in a style similar to his gang's former ways and asks Homer to bring the gang back together; Lenny and Carl (who have become police officers) join them. They attack an Eyes Wide Shut-style masked orgy and several other of Stanley Kubrick's films are parodied in a fight sequence. As Moe gets beaten by two party guests, he narrates that he was "Beaten, bruised" and "couldn't score at an orgy" but was happy to be back with his old gang. Kubrick is then shown in an editing room and asks for the entire film to be re-shot.

In a parody of The Others, the Simpson family find unexplained frosty chocolate milkshakes and that their TV only shows Married... with Children. After a ghost attacks him in his sleep, Homer summons the ghosts, who are the family's former selves from The Tracey Ullman Show. Homer is attracted to the ghost Marge who prefers him to the former grumpy Homer, so the jealous living Marge kills herself to become a ghost. The ghost Homer becomes jealous and bludgeons the living Homer to death with a toaster while he is in the bathtub. Bart fakes suicide to join the ghosts, tricking Lisa into actually killing herself, her ghost then murders Bart as revenge. Groundskeeper Willie takes the children's corpses to make stew and it is implied that he murdered Maggie. Homer chooses his modern-day wife over the older ghost. The next morning at the breakfast table, Lisa asks if there could ever be any other incarnations of the Simpsons and a range of Simpson families based on other animations are then shown. The segment ends with the original version of Homer unsuccessfully trying to photograph a good portrait of the two families together.