Apple Lisa mentions that nobody wants her just because she is an apple, and she thinks they might be frightened if there was a razor blade in her. This is a reference to an urban legend where news reports say that children supposedly received candy apples with pins and razor blades in them during the 1960s and 1970s.
The title of this segment is a spoof and reference to "The Exorcist". The segment also parodies the film throughout.
The demonic possessed Maggie breathing out fire is similar to what the demonic possessed Mr. Jerry Lansing did to Father John Lansing in the 2003 film "Exorcism".
The demonic possessed Maggie spinning her head 360 degrees is another reference to "The Exorcist", and is the second time to refer the 360 degree head scene; the first being Treehouse of Horror with Maggie as well. Bart's head spinning 360 degrees when Pazuzu possesses him is another reference to the scene.
After Ned suggests to perform an exorcism on Maggie, Reverend Lovejoy replies that he's afraid they didn't teach him those at Pepperdine University. While the THOH series is non-canon, this implies that Lovejoy got his divinity degree at Pepperdine University, but apparently didn't minor in demonology.
After the Irish Priest asks Marge and Homer to cut the possessed Maggie loose, he tries to put them at ease by saying that if you can't trust a Catholic priest with a child, who can you trust. This is a reference to the Catholic Church's cover-up of priestly child abuse.
After Pazuzu enters Bart's body, he claims that Bart has a darker soul than anyone it ever possessed, which is worse than working for David Schwimmer. This is a reference to former co-stars' allegations that Schwimmer was difficult to work with.
The last time Homer got his finger cut off was in Trilogy of Error (however, in that episode, Marge accidentally cut off Homer's thumb, while in this episode, Homer got his finger cut off by himself while trying to cut his forgotten hot dog (which was still frozen), and later cuts the rest of his fingers off when he was cannibalizing himself).
Game of Thrones - Mentioned during the disclaimer at the beginning when Lisa says that the segment is so disgusting that you will watch Game of Thrones to calm down.
Home Alone - Ned calls Homer "Homer Aloner" while greeting him.
Breakfast at Tiffany's - Mentioned by Homer when he answers Bart's question about the oven mitts on his hands after Bart and the rest of his family come back from Ohio. Homer replies that he was watching the movie and thought he could be more elegant. Homer's oven mitts also allude to Holly Golightly's iconic look from the film and poster (where she wears a pair of long black gloves).
After Lenny wonders how the food industry managed to stretch Homer out (despite his status as a sizable gent), Carl tells him that they stretched him out with bits of Barney, Comic Book Guy, and horse meat, much to Lenny's horror about horse meat being mentioned. This is a reference and spoof to the 2013 horse meat scandal, where it was discovered in Europe that several suppliers to major brands contained up to one-third horse meat. Aside from the age-old taboo against eating equine flesh, beef suppliers have a long history of fluffing up their so-called 100% beef products with less-expensive horse meat.
At the end of the segment, Homer asks Jesus if he understands what it is like to have everyone eat of your body, but Jesus rolls his eyes while saying, "Yeah, like every Sunday, pal." This is a reference to the metaphoric weekly ritual where Christians and Catholics drink wine (or grape juice) and eat a communion wafer, which symbolizes ingesting the body and blood of Christ and absolving the consumer of their earthly sins.
This episode did not air in Australia on 7mate for the crude scenes in MMM... Homer.
This is the fourth Treehouse of Horror special to have one of the segments directly reference another segment, after "Treehouse of Horror XIV", "Treehouse of Horror XXIV", and "Treehouse of Horror XXVI". In this case, the beginning of Coralisa has Marge mentioning that Maggie cannot go with Lisa as she "still has a touch of Pazuzu", referring to her possession from "The Exor-Sis".
This is the first THOH special since "Treehouse of Horror V" to have an opening scene in which a Simpson character comes out of the curtain and speaks to the audience. In this case, it is used at the beginning of "MMM...Homer" as a disclaimer that the segment is disgusting, which also features Lisa speaking to the audience (but doesn't come out of the curtain that is behind her).
Despite the title card saying "The Simpsons Easter Special" at first before getting covered with chocolate and the dark chocolate words "Treehouse of Horror XXVIII", the show never had a proper Easter special (although there have been several episodes centered around the spring holiday).