"Treehouse of Horror XI" is a Halloween-themed episode from the twelfth season of the animated comedy series The Simpsons. It was first broadcast in the United States on the Fox Network on November 1, 2000, making it the first Simpsons Halloween episode to originally air after Halloween. All subsequent Halloween episodes of the Simpsons would first be shown in early November until "Treehouse of Horror XX" in 2009.
In common with all previous Halloween episodes of The Simpsons, the show is made up of three self-contained stories; "G-G-Ghost Dad", "Scary Tales Can Come True" and "Night of the Dolphin". In the first story, Homer Simpson dies and has to do one good deed to avoid going to Hell. The second story is a retelling of the fairy tale "Hansel and Gretel" in which Bart and Lisa Simpson are taken prisoner by a witch. The third story is a parody of the 1973 science-fiction thriller movie Day of the Dolphin and also contains visual references to the 1993 movie Free Willy and Alfred Hitchcock's 1963 suspense film The Birds. The aliens Kang and Kodos make a brief appearance at the end of the episode.
In the opening credits sequence, the Simpson family appear as the monster characters from the 1960s comedy series The Munsters. Homer Simpson appears as the Frankenstein's monster-like Herman Munster, Grandpa Simpson as the Count Dracula-like Grandpa Munster, Marge Simpson as the vampiric Lily Munster, Bart Simpson as the werewolf Eddie Munster and Lisa Simpson as the normal-looking Marilyn Munster. An angry mob armed with pitchforks and torches suddenly appear and attack and kill the monsters. Lisa Simpson, because she looks like an ordinary person, is unharmed and tries to walk away, pretending that she has no connection with the monstrous family.
At breakfast, Homer Simpson reads his horoscope in the newspaper. He is surprised to read that it says he will die that day and receive a compliment from an attractive colleague. His wife Marge reads her horoscope, which says that her husband will die that day. On his way to work, Homer narrowly avoids death several times. At work, his co-worker Lenny compliments him on the rattlesnake on his arm. Homer continues to narrowly avoid several fatal accidents at work. When he returns home, he is confident that he will survive the day. Homer eats some broccoli for dinner and dies instantly. The Simpsons' family doctor explains that broccoli is the most deadly of all vegetables.
Upon arrival in Heaven, Homer is told by Saint Peter that he cannot enter because he never did a single good deed in his life. He is returned to Earth as a ghost and given twenty-four hours in which to perform one good deed. Homer tries to prevent his son Bart from being bullied but ends up getting a noogie from the bully himself. He tries to help the elderly Agnes Skinner across the road but causes her to fall to her death.
One minute before his twenty-four hours on Earth expires, Homer rescues a baby from a runaway stroller, just before the stroller runs into traffic and explodes. Homer returns to Heaven but Saint Peter tells him that, unlike Santa Claus, he does not see everything and was not watching when Homer did his good deed. Homer is sent to Hell where the Devil gives him a noogie for all eternity.
"Scary Tales Can Come True"
The Simpson family are peasants who live in a pumpkin cottage in a fairy tale world. Homer Simpson loses his job as the village oaf. Unable to support his family anymore, he abandons his children Bart and Lisa in the forest. Lisa carries a book of Grimm's Fairy Tales, and, knowing the stories, she and Bart Lisa are able to avoid many of the dangers in the forest. When they arrive at a gingerbread house, Lisa quickly recognizes it from the story of "Hansel and Gretel", but Bart is too busy eating candy to heed her warnings. Soon, the children are prisoners of a witch, Bart is being fattened up to be eaten and Lisa is chained up and forced to do housework.
When the time comes for the witch to cook the children, Lisa tries to delay her by mocking the witch for being lonely. The witch claims to have a boyfriend named George Cauldron but Lisa does not believe her. Homer Simpson arrives, eating his way into the gingerbread house. He had gone in search of the children because his wife Marge said that he should not have abandonned them - the couple could sell their children instead. The witch casts a spell to change Homer into a part fish, part chicken creature with broomsticks for arms. She tries to push Homer into the oven but he overpowers the witch and pushes her into it instead. A man named George Cauldron arrives, asking if the witch is ready for their date. Looking at the oven, Homer replies that she will be ready in twenty minutes.
Although the Simpson family remain poor they have no shortage of food, because the half-chicken Homer is able to provide them with a constant supply of eggs.
"Night of the Dolphin"
During a visit to Springfield's oceanarium, Lisa Simpson takes pity on its star attraction, the dolphin Snorky who is forced to do demeaning tricks. She releases the dolphin and he returns to the ocean. Having returned to the wild, Snorky plots to take revenge on the human race. He organizes an army of dolphins which begin to attack the inhabitants of Springfield. At first, they attack people on the ocean but later move onto land.
Snorky takes the stage at a town meeting. In perfect English, he tells the people of Springfield that long ago dolphins lived on land but were forced into the sea by humans. Snorky announces that, now that he is king, he will turn the tables on the humans and force them to live in the ocean. The people of Springfield fight against Snorky's dolphin army but are outnumbered and defeated. The segment ends with the Simpson family and other residents of the town trying to adapt to their new lives as marine mammals. The corpses of several people who have drowned form the words "The End".
The aliens Kang and Kodos, who had appeared in every one of the Simpsons Halloween specials since the first, complain about having been left out of the episode. They are cheered up when they receive a phone call, asking if they want to star in a series of commercials for a chain of clothes stores.