Critical Research Failure: Virtually every claim made related to Catholicism is the opposite of how it's actually practiced. For example, the priests claim at one point that a possessee would not be repelled by inverted crosses, as they are blasphemous symbols — forgetting that an inverted cross is actually known as a "Petrine Cross", a holy symbol associated with Saint Peter (who apparently requested to be crucified upside-down, feeling himself unworthy to share Christ's death) and his successor, the Pope. At another point, they claim that it is important to recognize the identity and infernal rank of the demon, when the Catholic guidelines are to completely avoid playing into the demon's ego and simply treat it as "the Devil, an enemy of Christ".
Critic-Proof: While a massive financial hit, both critics and audiences hated the film, to the point where it earned a rare F on Cinemascore. Then again, it's hard not for a wide-release horror film to be a hit when it was produced at the cost of only a million dollars.
Ending Aversion: If it's not considered the worst movie ending of all time, it's certainly put in the Top 5.
Ham and Cheese: Susan Crowley as Maria Rossi, one of the few lauded elements of the film because many found her over-the-top possessed antics entertaining.
Hype Backlash: Enjoyed a strong opening weekend, but all hype was squashed the moment audiences first viewed the infamous ending.
Memetic Mutation: The facts surrounding the Rossi case remain unresolved. Visit therossifiles.com for more information on the ongoing investigation.note This is exactly how the film ends: a text card with this caption. The website shown was shut down after just six months and is no longer operating, and did not actually have any information on the case. This was widely mocked by the media and audiences alike.
"The Vatican did not endorse this film nor aid in its completion". You know, unlike all those OTHER demonic possession movies that got the Vatican Seal Of Approval.
If you happen to understand Italian, watching the movie in English and hearing the heavy Eastern-European accents of some of the supposedly Italian secondary characters (while some scenes of movie were shot in Italy and Vatican City, many were filmed in Bucharest, Romania) ruins the suspension of disbelief, although it does add a layer of unintentional fun.
The bizarre Irish accent Maria takes on during the exorcism. Is she possessed by a leprechaun?