"Halloween of Horror" is the fourth episode of the twenty-seventh season of the American animated television series The Simpsons, and the 578th episode of the series overall. The episode was directed by Mike B. Anderson and written by Carolyn Omine. It originally aired in the United States on Fox on October 18, 2015.

It is the first Halloween-themed episode of The Simpsons that is not part of the show's Treehouse of Horror series.

The episode received highly positive reviews from critics.

The day before Halloween, the Simpson family completely decorates their house, calling it "Everscream Terrors". Homer stores the plastic skeletons too close to the furnace, and he decides to take the remains to Grampa's home and buy something new at the Halloween pop-up store. On their way to the store, Lisa and Bart see a sign advertising the upcoming Krustyland Halloween Horror Night, and share their excitement for it. At the Halloween shop, Apu gets angry at three lazy employees who are sleeping on their jobs, telling them to go back to work. While Homer is looking for a decoration to replace the skeletons, one of the workers gives Homer a deal where if he buys one "Señor Skeleton", he will give Homer a set of four of them for free. Homer accepts the deal and tells Apu about it, who promptly fires the workers. The three then vow revenge on Homer.

Later, Homer takes the children to the Halloween Horror Night. Lisa gets scared by the costumed people and tells Homer that she wants to go home. Although Homer tells her that the Horror Night is not scary, Lisa gets separated from her father, and gets even more scared by the zombies, as well as more costumed people, leading to the park being closed. At school, Lisa's unsettling experience causes her to develop a fear of Halloween decorations, becoming scared from even the simplest Halloween figures such as paper zombies and pumpkins. In horror, she then hides inside a locker, only to be rescued later by Marge. Back home, Marge tells Homer they should shut down Everscream Terrors for Lisa's sake, making both Homer and Bart upset. As Marge takes Bart and Maggie to the most famous Halloween block party at a cul-de-sac in Springfield, Homer tries to bond with Lisa, offering to do a puzzle with her at home. Meanwhile, the three disgruntled workers have come for their revenge, and begin to stalk them.

Homer locks up the house to protect them from the three men; however, they are already inside the house. He tries to take Lisa to the Flanders' house, but she runs back inside to get Tailee, a fur toy raccoon tail from early childhood that brought her comfort. Homer rushes to save her, only for them to wind up face-to-face with the home invaders. The two run up the stairs and hide in the attic, and the invaders are unable to find them.

Marge arrives at the block party with Bart and Maggie, but they are told by the security guard the party is for residents only after visitors wrecked last year's party. After unsuccessfully trying to bribe the security guard into letting them in, Marge tries to take Bart and Maggie trick-or-treating, but it is late out and all the children are asleep. The adults of Springfield come out in their mostly suggestive costumes and a musical number about adult Halloween follows (the musical number, "NC-17 Halloween", is a parody of "Time Warp" from The Rocky Horror Picture Show).

At the Simpsons' house, Homer apologizes to Lisa for having not listened to her the night before, and admits that he gets scared of things too, but encourages her to not let her fears prevent her from using her thinking skills. They decide to use their various holiday decorations to signal for help, but they accidentally activate the Señor Skeletons, giving away their hiding location to the three men. Homer climbs onto the roof to light up the 4th of July fireworks, but the strong wind extinguishes the matches. Lisa then remembers that Tailee is made of face oil-soaked polyester and will burn easily, and decides to sacrifice Tailee and light the fireworks to attract people's attention. This plan is a success, and the whole neighborhood wakes up. The home invaders are then arrested by the police almost immediately, and Homer rebuilds Everscream Terrors, so the whole town can enjoy it as Lenny and Carl arrive dressed as Kang and Kodos. Lisa, now unafraid of the decorations, also joins in the fun, and manages to scare Marge just as she arrives home with Bart, who is delighted to see the house decorated again.

During the end credits, Maggie finds the half-burnt Tailee which magically restores itself to the tune of John Carpenter's Halloween.

This is the first Halloween-themed episode outside of the Treehouse of Horror series.^[1] Because it is the first Halloween episode to take place in the canonical Simpsons world, the producers wanted to include as many Halloween themes as possible. Writer Carolyn Omine based Lisa's fear on her own childhood experiences and those of her son and niece. She also incorporated her parental behavior into Homer's ability to protect Lisa. Tailee is based on a doll that director Mike B. Anderson's daughter used as a security blanket. Executive producer Matt Selman liked the episode's idea of showing the difference between the fear of what is real and the fear of what is not real.^[2]

Nick Kroll and Blake Anderson were cast as Halloween store employees who lose their jobs because of Homer. Kroll called the appearance a "lifelong dream."^[3]

Homer whistles the main theme from the 1978 film Halloween.^[4][5] It also plays over the end credits.^[4] In the third act, Kent Brockman wears a Ziggy Stardust costume.^[6]