Treehouse of Horror XXI/References

Opening

 * Professor Frink walks past an X-ray machine, revealing that he has an Alien inside him.
 * Frink has created his own.
 * Frink's DVR remote references the comedy film .
 * References to :
 * Frink's monster makes a couple of references to the show.
 * Frink's monster and some other monsters have a scene that parodies the show's opening sequence.
 * The first frame of the episode's opening credits has the same font and layout as The Office.

War and Pieces

 * The segment is a parody of .
 * Board games that come to life include:
 * Taffy Land
 * Drops and Risers
 * Consternation
 * Ravenous Ravenous Rhinos
 * Mouse Catch
 * Battleboat
 * Funopoly ( and Monopoly variations)
 * Crate of Apes
 * Yahtzu
 * Tiddlywonks
 * Satan's Path
 * Connect Three
 * Kerplunk (various building games)
 * Blocko
 * Mystery Dude
 * Milhouse's death scene in the segment is almost identical to Jack Dawson's in .
 * Colonel Ketchup is a parody of, who himself has occasionally appeared alongside Springfield's wealthiest.
 * When Bart says "...it's time to beat the crap out of childish things" he is alluding to Paul's first letter to the Corinthians.
 * Bart, Milhouse and Reverend Lovejoy play on a.
 * Milhouse's death scene in the segment is almost identical to Jack Dawson's in .
 * Colonel Ketchup is a parody of, who himself has occasionally appeared alongside Springfield's wealthiest.
 * When Bart says "...it's time to beat the crap out of childish things" he is alluding to Paul's first letter to the Corinthians.
 * Bart, Milhouse and Reverend Lovejoy play on a.
 * Milhouse's death scene in the segment is almost identical to Jack Dawson's in .
 * Colonel Ketchup is a parody of, who himself has occasionally appeared alongside Springfield's wealthiest.
 * When Bart says "...it's time to beat the crap out of childish things" he is alluding to Paul's first letter to the Corinthians.
 * Bart, Milhouse and Reverend Lovejoy play on a.
 * When Bart says "...it's time to beat the crap out of childish things" he is alluding to Paul's first letter to the Corinthians.
 * Bart, Milhouse and Reverend Lovejoy play on a.

Master and Cadaver

 * The title is a pun on the 2003 movie .
 * The plot parodies .
 * Marge drinks champagne.
 * At the end, Maggie imitates Alex from A Clockwork Orange.

Tweenlight

 * The series is punned in the title and parodied throughout the segment.
 * The last vehicle Edmund stops from running over Lisa is a driven by Otto.
 * Yogi Bear makes a cameo appearance, carrying Ranger Smith's head in a picnic basket.
 * Milhouse's jealousy of Edmund, and his resulting transformation into a, are a parody of the Twilight character and his family's ability to transform into wolves.
 * Seen in Dracula-la Land:
 * Grandpa Munster
 * Michael Jackson
 * Blackula
 * Nosferatu
 * Booberella
 * Count von Count
 * Count Dracula
 * Count Fudge-ula
 * Selene
 * When Count Dracula spots Edmund climbing a bell tower and carrying Lisa on his back, Homer immediately jumps onto Dracula's back, expecting the same transport. Dracula staggers under Homer's weight and protests that he's Dracula, not the Hulk.
 * At one point, Edmund exclaims "You're tearing me apart!" to his father, referencing a scene from .

Trivia

 * This is the first Treehouse of Horror episode since THOH V to warn viewers not to watch it.
 * The is heard at a couple of places in the episode:
 * During the "War and Pieces" segment, when Bart and Milhouse kill enemy characters in the video game they're playing.
 * After the closing credits (instead of the usual "Treehouse of Horror" scream), when the Gracie Films card appears.
 * This episode was originally slated to premiere in the UK before the US premiere. However, it instead aired on November 11, 2010.