The Simpsons Halloween Special VIII (Season 9; Oct. 26, 1997)
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Intro: A FOX censor tries to eliminate any sex or violence from the episode so it can be rated TV-G. (The TV rating system went into effect in January of 1997, the same year as this episode.) But the rating bug itself kills the censor, so the show can do whatever it wants, I guess. Then there's a couch gag.
The HΩmega Man: In a parody of The Omega Man, Mayor Quimby starts a feud with France. They fire a nuclear missile at Springfield, while Homer is checking out a bomb shelter. When he comes out, he discovers he's the only person left alive... or is he? Either way, it's a pretty funny story.
Fly vs Fly: In a parody of The Fly, Homer buys a matter transporter from Professor Frink at a yard sale. Later, Bart uses the transporter and gets his DNA mixed up with that of a housefly. It's a fairly amusing and scary and gross story. (I really liked the bit with the spider.)
Easy-Bake Coven: In a parody of The Crucible, the story is set in 1649, when the people of Sprynge-Fielde are burning accused witches at the stake. Before long, they accuse Marge of being a witch. I don't want to reveal more than that, except that it ends up being the story of the first Halloween. So that was fun.
Anyway... watching this in 2020, none of it is familiar enough for me to be sure I've seen the episode before. But I probably did. (The final segment rings a faint bell.) Either way, I'm glad I've seen it now.