This episode is considered non-canon, and the events featured are not part of the timeline of the series' continuity.
“Ahem. Hello, everyone. Before last year's Halloween show, I warned you not to let your children watch. But you did anyway. Well, this year's episode is even worse. It's scarier, more violent, and I think they snuck in some bad language, too. So please, tuck in your children and... [sighs] Well, if you didn't listen to me the last time, you're not going to now. Enjoy the show.”
The sequel to the original Treehouse of Horror. In Lisa's nightmare, she dreams that Homer purchases a monkey's paw that grants the family four wishes. In Bart's nightmare, he dreams that he has the power to read minds, and he punishes people if they are not happy - subsequently turning Homer into a jack-in-the-box. In Homer's nightmare, his brain is put into a Frankenstein-style robot.
"Hello everyone. Before last year's Halloween show, I warned you not to let your children watch. But you did anyway. Hmm. Well, this year's episode is even worse; it's scarier and more violent and I think they snuck in some bad language, too. So, please, tuck in your children and... well, if you didn't listen to me last time, you're not going to now. Enjoy the show."
When Marge, Lisa, and Bart come back from trick-or-treating, they have a load of candy. Marge tells them not to eat too much or else they will get nightmares. They all scoff at her, but they do have nightmares (or at least Bart and Lisa do).
The Monkey's Paw
The Monkey's Paw is Lisa's nightmare. This story has the Simpsons visit Morocco, where Homer buys a mysterious monkey's paw that grants wishes but with great misfortune. Once back home (after Homer had to pay a two American dollar fine for attempting to smuggle souvenirs on board the plane), the family argues in how to use it. Marge warns them not to and heed the advice of the vendor. Maggie wishes for a golden pacifier, and Bart wishes for the family to be rich and famous. The pacifier does not seem to have negative consequences, but the money and fame cause a public backlash to grow around the Simpsons, as they appear on everything from T-shirts to billboards for mammogram tests. Lisa wishes for world peace, but when Kang and Kodos see that the Earth is vulnerable, they conquer it, enslaving humanity. Homer is enraged by her wishes, but Marge calls them back to their senses and everyone is blaming the Simpsons for this. Wanting the aliens gone, she begs him to make them leave. Homer refuses, pointing out that Marge was against the family using the monkey's paw and decides he's going to wish for something normal. He then wishes for a turkey sandwich without any "weird surprises," which he claims is a wish that can't backfire. The sandwich appears to be perfect... except the turkey is a little dry. This 'abnormality' causes Homer to fly into a rage, before throwing the monkey's paw away. When Ned Flanders sees Homer throwing it out, Homer offers the paw to him, assuming that wishes with misfortunes will soon plague his neighbor. However, Ned's first wish (to get rid of the aliens) frees the human race and he is considered a hero. Shortly afterward, Flanders wishes for his home to become a castle, as Homer watches, seething.
After Lisa has her nightmare, she goes into Bart's room and wakes him up to ask if she could sleep in his bed. Bart tells her to get lost, so she offers him a candy necklace. He eats it and spits the string out, and tells her she can sleep with him. She climbs into his bed and thanks him. He replies,"less talk, more sleep." as he spends the last moment staring at the Krusty the Clown Jack-in-the-box on his bed table before going back to sleep.
The Bart Zone
In Bart's nightmare, which is a parody of The Twilight Zone episode "It's a Good Life", he is a boy with the ability to bend reality with his mind, as well as read the minds of others, and he will turn anyone who thinks badly about him into a creature. The entire town lives in fear of him because of this gossip, constantly forced to be happy and fulfill his every demand. Bart comes home from school and Homer and Lisa are watching TV. Bart demands to watch Krusty, but after Homer refuses, Bart replaces the football on the TV with him and he smacks into the field post. When Homer comes back, he tries to bash Bart over the head with a chair. Bart reads his mind and turns him into a Jack-in-the-box. Upon discovering this, Marge takes them to see Dr. Marvin Monroe, who suggests that Bart and Homer spend more time together doing father/son activities. Homer takes Bart to a baseball game, fishing, shooting a BB gun, church, and to an amusement park. Bart becomes less mean as he enjoys the time with his father, and chooses to turn Homer back to normal. Homer then gives Bart a fatherly kiss and Bart wakes up, screaming in terror. Meanwhile, after Bart had his nightmare, he and Lisa run into Homer and Marge's room and ask to sleep in their bed. Homer looks at the clock and comments that in two hours he has to get up and go to work.
If Only I Had a Brain
In Homer's dream, Homer is fired from his job for sleeping and he becomes a gravedigger. He falls asleep in an open grave. Mr. Burns and Smithers are out looking for a brain, for their experiment to create the ultimate worker. They find Homer, and thinking he is dead, put him in a bag, take him to their lab, remove his brain and place it into a robot. The robot then acts like Homer (clumsy, lazy, and the love for donuts), much to Mr. Burns' disappointment. Smithers convinces him to put Homer's brain back where it came from, but after this is done the robot falls on top of Mr. Burns, crushing his body. To save his life, Mr. Burns' head is sewn onto Homer's body. Homer wakes up from his nightmare and realizes that Mr. Burns' head really is sewn onto his body. Later, as the Simpsons are eating breakfast, Lisa reminds Homer that the kids' school will be having an all-you-can-eat spaghetti dinner that evening. Homer looks forward to it, but Mr. Burns reminds him that same evening, they will be attending the reception for Queen Beatrice in the Netherlands. Homer complains then that he hates having two heads.
The Simpsons Treehouse of Horror II Promo (Fox Halloween Bash 1991)