S11E4: Treehouse of Horror X

In "Simpsonlar - S11E4," also known as "Treehouse of Horror X," the episode wraps up with three distinct segments, each with its own peculiar conclusion. In the first segment, "I Know What You Diddily-Iddily-Did," the Simpsons are haunted by what they believe to be the ghost of Ned Flanders, whom they accidentally killed. The twist is that Flanders isn't dead; he's a werewolf, and he attacks them in a rather literal cliffhanger. The second segment, "Desperately Xeeking Xena," features Bart and Lisa as superheroes trying to save Lucy Lawless from the Collector, a villain who is an obsessive nerd. The siblings manage to defeat the Collector by freezing him in carbonite (yes, like Han Solo), but not before some amusing fan-service moments involving Lawless' character. Finally, in "Life's a Glitch, Then You Die," Homer accidentally causes a Y2K apocalypse by failing to fix the Springfield Nuclear Power Plant's computer systems. As chaos ensues worldwide, Homer and Bart manage to secure spots on a spaceship meant for Earth's best and brightest, only to find out it's actually headed straight into the sun. Meanwhile, Lisa and Marge make it onto another ship that's off to start a new civilization on Mars. So, the episode ends with Homer and Bart listening to Rosie O'Donnell sing on their doomed vessel.