Treehouse of Horror XVIII (Season 19; Nov. 4, 2007)
Amazon; Disney+; Halloween Specials Wiki; Halloween Wiki; IMDb; Simpsons Wiki; TV Tropes; Wikipedia

Intro: Marge starts talking about the episode, but is distracted by network bugs for other shows, which she has to eliminate. That was fun.

E.T. Go Home: In a parody of E.T. The Extra-Terrestrial, Bart finds Kodos hiding in the Simpsons' shed and befriends him. Kodos just wants to build a device to call his people, or so he says. Anyway, it's reasonably amusing.

Mr. & Mrs. Simpson: In a parody of Mr. & Mrs. Smith, it turns out Homer and Marge are, unbeknownst to each other, both assassins. So, naturally, they try to kill each other. It's reasonably amusing.

Heck House: Bart, Lisa, Milhouse, and Nelson are out trick or treating, when they decide instead to just focus on the "trick" part, and cause a lot of mayhem. Then Ned tricks them into going into the church, done up as a haunted house, to scare them into stopping their misbehavior. It's reasonably amusing.