Light and darkness play an important role in every religion. When it comes to Christianity, however, Catholicism is by far the most associated with dark elements, including exorcisms, evil hidden behind a collar or more mundane ones like corruption, and a very controversial history (which, however, isn't uncommon when it comes to religion). Unless these things are portrayed as literal light, in which case it's all light.
Creepy Catholicism embraces the description of Catholicism either as simply uncanny and dark or outright criminal and corrupt, especially if compared with other religions. This portrayal is typical of countries characterized by a Protestant majority. Once the Protestant Reformation got going, many Catholic traditions were suppressed. The sort of very bloody and gory art (crucifixes, frescoes of martyred saints, etc.) and ostentatious church decor popular among Italian, Spanish, Portuguese and Latin American Catholics, for example, can be quite shocking to someone from one of the more austere Protestant sects that favor plain wooden crosses and unadorned churches.
So if a writer wants to evoke the sort of mood and creepy factor of a pagan sacrifice or incomprehensible witch-doctor ritual, yet make it Christian, then the creepier sort of Catholicism is the way to go, especially once you toss in some Ominous Latin Chanting.
Truth in Television much of the time, since Catholicism retains many of the "otherworldly" traditions discarded by Protestant churches (the aforementioned Latin chanting, exorcisms, Purgatory, transubstantiation), some of which might seem like something straight out of a horror film to non-Catholics, especially children. That isn't to say that certain Protestants don't also have some spooky beliefs and rituals (snake handling, speaking in tongues, the Rapture, beliefs about demons, some more exorcisms, etc.). And of course, more knowledgeable Catholics might point to Orthodox Christianity as being even spookier: besides keeping the same beliefsnote and medieval trappings — and then some — you think the chanting is ominous when it's in Latin? Try it in archaic Greek, or Syriac, or Old Slavonic, or Coptic (which is Ancient Egyptian with some Greek tossed in), plus people prostrating themselves and hermits going into really weird kinds of meditation. Catholics in general were historically also more open to science and magic (relatively, of course; one can list many heresy cases for either, after all), having an extensive number of scientists and alchemists under its name, so it is a lot easier to demonize Catholicism as demonic or "false Christian" than other Christian groups, which often tend to reject science and/or magic.
Counts as Religious Horror if the work focuses on it. Creepy Cathedral and Hollywood Exorcism are generally associated with this trope. If a Pedophile Priest or a Sinister Minister appears, he'll probably be Catholic (but not always). May have something to do with Christianity is Catholic. Anime Catholicism may overlap with this trope.
- From Black Lagoon, "The Church of Violence" run with an iron fist by Sister Yolanda, an (apparently) elderly nun who wears an eyepatch and a fully — loaded, custom Desert Eagle pistol under her habit at all times. The church is not actually an official subsidiary of the Catholic Church, it's a cover for a gunrunning operation that is funded by the CIA.
- Blue Exorcist, where Satan is the Big Bad and The Vatican are supposed to be the Big Good. The main characters (one of which is a child of Satan) are studying at a school for exorcists to learn how to fight demons.
- The Vatican in Hellsing is portrayed as a rather dangerously fanatical organization with a violent hatred of Protestants and other non-believers. They are technically a force for good, since they fight against monsters and vampires as well, but their Knight Templar actions in the series make them secondary antagonists.
- If Chick Tracts are to be believed on this matter, Catholicism is an Ancient Path of Inspiration responsible for both world wars, Nazism, Communism, Freemasonry, Islam, Mormonism, Jehovah's Witnesses, and even Jack Chick's fellow Protestants removing his tracts from their bookstores because they were sick of his inaccurate, hateful, and all-around bizarre claims.
- Nightcrawler from X-Men is a devout Catholic, but his demonic appearance is seen as scary by many, and he has an affinity for shadows, which emphasize the "dark" elements of his character. On the other hand, he had a cheerful and nice personality. The film version plays this trope straighter by giving him a more introverted personality and self-inflicted scars as a way to atone for his sins.
- In The Blues Brothers, the title characters go "to see the penguin" — who turns out to be not the Batman character but rather a very stern, heavyset, intimidating Catholic nun who wields a wooden 1-foot ruler like a martial arts weapon and moves with a Ghostly Glide.
- Constantine (2005): Several of the characters fighting against demonic incursions are Catholics, one of whom is a priest (Father Hennessy). The title character uses Catholic rites against demons, including exorcism and the Last Rites, and is definitively an Anti-Hero.
- The Exorcist and every other movie dealing with Christian exorcism. Interestingly, The Exorcist had a Jesuit priest and teacher as a technical advisor (he also played the part of Father Dyer). The priest stressed that the Catholic Church typically doesn't condone exorcisms anymore and it is something of an Old Shame within the church.
- Angels & Demons: Religious buildings in Vatican City are used as locations for the murders. Also, the description of the papal conclave wouldn't be out of place in a locked room mystery.
- The Da Vinci Code: Features the self-mutilating monk Silas, a member of a heavily fictionalized version of the Catholic Opus Dei organization and one of the main antagonists. Silas himself is definitely meant to exude creepy, but Opus Dei itself is characterized as a sinister secret society in service to the Pope and a part of an Ancient Conspiracy. As you can imagine, this portrayal rather annoyed the Real Life Opus Dei organization, which is mostly just a lay Catholic group with no real power.
- Dracula averts this, despite it being very common in Victorian literature. Van Helsing is a Catholic scientist who uses his religion's iconography to fight against the powers of the night. This is remarked on by protagonist Jonathan Harker, who finds it ironic that he puts his faith in a crucifix when as a child he was taught that it was a symbol of idolatry.
- Empire of the Vampire: Given the heavy and liberal usage of high medieval Gothic architecture, dark clothing, Ominous Latin Chanting or a plethora of rituals and rites involving the drawing and imbibing of blood, Kristoff definitely enjoys making use of this trope. This not even mentioning the more mundane horror within the Church, including priestly corruption, rising fanaticism or certain priests being exposed as allies of the Dead. That said, for all their many flaws and sinister imagery, the Ordo Argent and the Church factions aligned behind them are undoubtedly on the side of good.
- Hyperion Cantos interweaves Catholicism and Hyperion's "cruciform," parasite. Initially something of a coincidence, the combination becomes tighter as the series progresses, with the revitalized church being antagonists of the second story arc.
- M.R. James' ghost stories vary in their premise, but several of them rely on this trope.
- His first published story, "Canon Alberic's Scrap-book," involves a medieval French cleric and a haunted drawing of a demon, which creates problems for the English academic who collects the titular scrapbook.
- "The Treasure of Abbot Thomas" also features a medieval cleric with some interesting secrets, this time in Germany.
- In-universe in "The Ash-Tree", a mysterious death that occurs in rural 17th-century England is blamed by some on a "Popish Plot."
- In The I, Richard Plantagenet Series Catholicism infuses every aspect of all the characters lives. Sometimes, it's quite a positive force, such as monasteries serving as Medieval Air B&Bs, but often it's quite eerie. Monks spy on Richard and Anne while she is in sanctuary, shrines and chapels are described in otherworldly detail and characters are perpetually praying and confessing. Even The Hedonist Edward IV puts himself into a trancelike state while praying. Moreover, this is a world where the church has power and if you break the rules, such as committing bigamy, that matters.
- Melmoth the Wanderer: Spanish Catholicism is presented as a violent Religion of Evil that indoctrinates its monks and is ruled by power-seeking Evil Jesuits.
- The Gothic novel The Monk has its own page.
- The Criminal Minds episode "Demonology" revolves around a priest suspected of murder and an exorcism.
- Embraced by the band Ghost. They perform in elaborate costumes based on Catholic vestments, their official logo uses an inverted cross for the T, and most of their album art is horrific riffs on Catholic imagery. This extends to their titles and contents of their songs, with their biggest hit being, "Mary on a Cross."
- Lady Gaga plays a lot with this trope, the most evident example being the video of "Alejandro", where she is dressed in a latex outfit that resembles a nun's habit and swallows a rosary.
- Revocation's "Communion" depicts a cannibal cult Catholic sect.
- Brave New World supplement Covenant. The Catholic Church has a secret group of heroes with superpowers that fight against the demonic influence and other supernatural monsters.
- Through extensive and chillingly visceral Crystal Dragon Jesus, Magic: The Gathering has made an art out of portraying fantasy Catholicism as corrupt and fanatical. Naturally, it is always white-aligned (except for a few examples dabbling with black-magic).
- In Dominaria, the old Church of Tal had elements of medieval Catholicism, both aesthetic (Templar-like knights, black-wearing priests, witch hunters) and philosophical (witch hunting, taking specific literature as key above all other forms of religious expression). A religious institution devoted to purging their world of magic, they were revealed to be hypocrites using White Magic spells and lost their political power.
- Ravnica's Orzhov Syndicate is very blatantly ripped off visually from the Catholic Church and holds a similar hierarchy (aside from a pope). They promise salvation to the people of Ravnica but are essentially a mafia group under a holy façade.
- Ixalan's Church of Dusk lifts from historical conquistadores and their fanatical religious obsession. Combined with being literal vampires, it's not hard to see the commentary on Catholicism from that era.
- TORG has the Cyberpapacy, which is this trope after it got a forced cosmic infusion of Cyberpunk. It includes circuitry-enscribed crucifixes, a virtual Purgatory and an omniscient electronic surveillance net that keeps the Inquisition informed of all your sins.
- Many of Warhammer 40,000's more outlandish religious elements (concerning the Imperial creed, the Dark Gods are something else entirely) are Flanderized elements of Catholicism: everyone wears hooded robes, exorcisms are a necessity (one Space Marine chapter even uses it as part of their initiation), pipe organs are mounted on tank treads to provide inspiring hymns and missile support... old canon even implied the Emperor was Jesus and Saint George in one of his many "guide humanity towards betterment" disguises, but new canon only kept Saint George (replacing the dragon with the C'tan star vampire called the Void Dragon and "killing" it by locking it up on Mars).
- The Old World of Darkness has the Society of Leopold, a secret organization that began within the medieval Catholic church and specializes in hunting and killing supernatural creatures. While they fervently believe they are serving as soldiers of Christ against the army of the Antichrist, in practice, a lot of their behavior amounts to Van Helsing Hate Crimes, willing to use torture and murder against any supernatural entity regardless of whether they've committed any crimes.
- Blasphemous is a Metroidvania game with horror elements that draws heavily from Catholic imagery, especially its practice in Spain. The plot takes place in a morbid world that venerates guilt and pious suffering as the result of a “Grievous Miracle” that deals out blessings and curses arbitrarily and causes sins to manifest as physical plagues and twist people into abominations.
- The Shimousa chapter of Fate/Grand Order has the segment's Big Bad Evil Sorcerer using "Jesuit sorcery" mixed with Buddhist sutras in the name of Satan to summon Heroic Spirits and corrupt them into murderous maniacs except not. All of the references to Christianity and even Dante's The Divine Comedy are merely The Man Behind the Man screwing with people for shits and giggles.
- There are many memes in which Benedict XVI is compared to Senator Palpatine.
- The Simpsons: The episode "The Father, the Son, and the Holy Guest Star" has Bart sent to a Catholic school, where great emphasis is put on martyrdom and suffering.