Treehouse of Horror XVIII/References

Cultural references

 * Many parts of the segment "E.T., Go Home", are references to the film ', with Bart in the role of Eliott and Kodos as E.T. The "Mr. and Mrs. Simpson" segment is a parody of the 2005 film '. In the final segment, "Heck House", Groundskeeper Willie's tractor transforms into a robot and kills him, parodying Transformers.
 * A multitude of aliens come through the portal to the music of ' by, reminiscent of the multitude of broomsticks come to life in the movie '.
 * Soldiers and helicopters come to battle the aliens to 's ', reminiscent of that music used to similar purpose in the movie '.
 * Surreal scene of hell is a homage to the painting  by.
 * Jimbo, Dolph, and Kearney comprise the 3-headed dog in hell, a reference to, the 3-headed dog that guarded the entrance to the Underworld in Greek and Roman mythology.

Trivia

 * This is the first Treehouse of Horror to have the opening credits appear on the same location as the title.
 * As part of Halloween Tricking rampage, Patty and Selma have been tarred and feathered (but are still smoking); Moe has over a dozen mousetraps attached to his body and clothes.
 * This is the second time that Ned Flanders becomes the devil. The first was in "Treehouse of Horror IV".

Continuity

 * Toys found in Bart's room include:
 * A Funzo ("Grift of the Magi")
 * A Linguo ("Trilogy of Error")
 * A Phonic Frog ("Smart and Smarter")

Goofs

 * The aliens come out of the portal, however in the next scene, the aliens just start coming out, although in the previous scene a few had already come out.
 * Homer and Marge hide their guns from Bart and Lisa, and the guns just appear out of nowhere. Next, Marge puts her hands down, and the gun's disappeared again. Then, when Bart and Lisa go back upstairs, Homer puts his hand down and his gun's disappeared.
 * Bart, Milhouse, Lisa and Nelson start throwing water balloons from behind a bush, but when Bart runs to the three to start throwing balloons, they are not behind a bush.
 * The Simpsons' house roof is flat.
 * When Marge puts the logo Hugh Laurie in the microwave, he splatters in the corner. Next shot the splatter is in the middle of the microwave.