It's The Grand Pumpkin, Millhouse
Treehouse of Horror XIX
I love a well done parody, and this one take a beloved children's classic (It's The Great Pumpkin, Charlie Brown) and puts that hilarious Simpson's spin on it.
Millhouse believes that the Grand Pumpkin will visit the pumpkin patch on Halloween (Bart made it up) and Lisa waits with him. Just when they think he won't show up, the Grand Pumpkin arrives and greets the two children. Unfortunately, he learns that pumpkins are mutilated and cooked by humans, and so begins his revenge by eating Homer, Nelson, and Willie.
Lisa realizes that Millhouse's childlike belief is what brought the Grand Pumpkin to life, so she tells him about Tom Turkey, a Thanksgiving legend. Tom Turkey kills the Grand Pumpkin, but upon learning that humans eat turkeys, he begins his killing spree as Marge wishes everyone a Happy Halloween.
Milhouse: I like your witch costume, Lisa.
Lisa: I'm not a witch, I'm a Wiccan. Why is it that whenever a woman is strong and powerful, they call her a witch?
[Muted trombone vocalizes]
Lisa: You said something, mom?
Marge: No, I was just practicing my trombone.
Nelson threatens to stab a yellow pumpkin, to which the Grand Pumpkin replies that he doesn't care because all pumpkins are racist, and then proceeds to eat Nelson anyway.
Clown Without Pity
Treehouse of Horror III
Based on the Twilight Zones episode Living Doll, Homer purchases a gift cursed Krusty doll for Bart. The doll then continuously tortures Homer until a repairman can arrive to reverse this evil. This evil being programmed into the doll and causally switched by the flip of a switch from Evil to Good which turned the curse into a blessing as Homer finds a pal to do his chores.
*Homer walks into the House of Evil store*
Homer: Do you sell toys?
Storekeeper: We sell forbidden objects from places men fear to tread. We also sell frozen yogurt, which I call frogurt.
The doll makes its first attempt to murder Homer, the family doesn’t believe his pleas. Slowly, the Krusty doll walks towards Homer laughing only to get a few inches before his pull-string needs to pulled in order to keep laughing. Homer, of course, helps out.
Terror at 5 1/2 Feet
Treehouse of Horror IV
In a spoof of my (Matt) personal favorite Twilight Zone episode, Bart has a nightmare about the school bus crashing, and is on edge the whole ride to school. His paranoia is justified once he notices a small gremlin-like creature starting to dismantle the bus. True to the episode's source material, he is the only one that can see the monster, and no one believes him when he points it out to him.
The gremlin nearly destroys the bus but Bart ends up throwing a flare at it at the last second. It is later picked up by Ned Flanders. Once the bus arrives at the school, everyone sees the damage the gremlin caused to it, but Bart is carted off to an insane asylum anyway (exactly like William Shatner's character in Nightmare at 20,000 Feet). He finally starts to relax in the back of the ambulance, when the gremlin shows up in the window holding Flanders' disembodied head, causing Bart to scream.
Bart: Milhouse, Milhouse, wake up! Look out the window!
Milhouse: Now way, Bart. If I lean over I leave myself open to wedgies, wet-willies or even the dreaded rear-admiral.
Bart ask Otto to do something about the Gremlin on the side of the bus. Otto looks to his side and sees Mole Man driving an AMC Gremlin and without hesitation knocks him off the side of the road. Mole Man's car slowly rolls towards a tree and with just the slightest touch, it explodes.