Treehouse of Horror XXX

"Treehouse of Horror XXX" is the 4th episode of season 31. It aired on October 20, 2019.

Opening sequence
It's Halloween, and Marge is having a new baby born, when from her womb comes out an unexpected boy. Homer is terrified of the prospective of a second Bart (who is completing text on a wall with graffiti to say "boner", so he asks Dr. Hibbert to change the baby, to which Hibbert gives them Maggie, but warns him "She tested positive for evil".

Maggie demonstrates her powers by choking Hibbert and then placing him in the baby incubator and having it going up all the way to 1.800 °F incinerating him. They take her home and she makes the toys' head turn and twist till all the fluff inside breaks out, burns the posters Homer places on the wall and eats and spits a bird in his face. Homer begins to ponder if it was the right decision.

At her birthday, she burns Gerald's hairs and make Kearney, Shauna and Dolph hang themself from the window and Ned decides it's time to stop this, especially after she changes Rod and Todd to be bad boys, saying he'll perform three funerals that night.

At the cathedral, Ned is stopped by Marge, but he warns them she's bearing the mark of the beast, Mickey Mouse, before switching to the correct one, the number of the Beast, 666. Having not being killed, she destroys the ceiling of the cathedral and impales Homer, Marge, and Ned.

Danger Things
In the '80s, at Bart's treehouse, Bart is playing E.T., with Martin, Milhouse and Nelson. After getting a game over, the kids split up to go back home on their bikes, when Milhouse gets attacked.

Luann and Kirk get worried as he hasn't come back at home, and Kirk starts busting the wall trying to find him. The police find his bike near the woods, while Kirk places letters on the wall to see if he's in another dimension and he can communicate with them.

Since Milhouse is gone, Luann confesses she's having an affair, and Disco Stu comes down the stairs revealing it's him. Milhouse sends an SOS with the letters but due to the problems they're having they send him and his lights "in his room".

At the Simpsons home, Lisa gets a call from Milhouse, but once she says she doesn't like him as a boyfriend, he hangs up. Lisa goes to the Starcourt Mall, which sign gets invaded by rats to become the Ratscourt Mall. The kids are playing at the arcade and she informs them of Milhouse being trapped in the other dimension, and he calls for them from the videogame Bart was playing.

They go to Professor Frink's lab to find a way in, and Lisa uses a sensory deprivation tank to find Milhouse. In the Over Under, Lisa finds Milhouse, but they're spotted by the that bites his left leg off when he doesn't stop talking.

They try to escape the Domegorgons in town, while other monsters devastate the city. Lisa reveals she has psychic powers but they're trapped until Homer saves them with a flame thrower, saying it was Mr. Burns opening the portal to find monsters for a government secret project. Homer informs them they're all trapped in the dimension so they sit down at the couch before finding out there's a Ned version of the Demogorgon and burns him.

Heaven Swipes Right
At the Springfield Atoms Stadium, Homer, Moe, Lenny and Carl are watching the Springfield Atoms vs. Shelbyville Shelbyvillians match, and when the crowd starts shouting choke, a hotdog ends up choking Homer to death.

Arriving in Heaven, he meets St. Greeter, who welcomes him with the pun on his name, but Homer doesn't forgive the pun so he gets damned to Hell. Homer finds out God sold Heaven to Google, before discovering he died before his time, but can't be sent back to Earth in his body due to the decay.

He could decide he could live the life of a man that was going to die that day, so Homer chooses a football player's body. He goes to Marge and she loves the new body, but he ruins it in one night. Bart and Marge convinces him to try Superintendent Chalmers as the next body.

At school, Homer makes Skinner give Bart all As and twist his nipple till its deep purple, and then goes to his house just to see he makes very little money and changes again, but Marge has had enough. Homer has to settle in for one body and stop changing, so he chooses the one of the man that loves her as much as he does, Moe, however Moe finds himself in Maggie's body and informs her he's thirsty.

When Hairy Met Slimy
At the Power Plant, Selma enters a maximum security door to sneak a smoke, and finds herself in a laboratory, where she meets Kang and they fall in love. After offering to provide the secret to clean, natural energy Mr. Burns wants to dissect him, so they flee, to go to a distant galaxy, with Homer's much-obliged help.

Selma and Homer sneak Kang out in a waste container full of rats, but Burns finds them. Kang bites off Smithers head and knocks out Burns, with Barney driving the trio out in his car. Mr. Burns and the military follow, but his driver is shot as they flee to Mt. Springfield. Thinking they're safe, Kodos arrives with a ship but a shooting takes place and Selma is hit in the stomach.

Kang then pulls out Thanos' infinity gauntlet to eliminate all military people, and when Burns survives, he hits him with a tin can. Kang then heals Selma and tells her he's pregnant.

Patty arrives, protesting they're too different, being of different zodiac signs, but Kang points out he's from Sagittarius. Patty begs her not to go but falls in love with Kodos. They fly to space, and find themselves on the honeymoon planet, in the cool season, where it's 4,000 °F.