Into your house, into your bed
Into your streams, into your streets
Into your drink, into your bread!
Upon your cattle, on your sheep
Upon your oxen in your field!
Into your dreams, into your sleep
Until you break, until you yield!
I send the swarm, I send the horde!
Thus saith the Lord!"
When The Plague is brought about not via natural evolution or the machinations of science, but is instead created through the supernatural powers of a person, creature, or group, whether by accident or design.
In classical works, Mystical Plagues are brought about by the gods or God to punish society for some collective sin. The plague invites some investigation into who offended the divine and how to make up for the damage.
Fantasy uses of the trope are less positive. Perhaps a Necromancer is summoning dark magic to bring about the Zombie Apocalypse, worshippers of the God of Disease call upon their master to bring vengeance upon their enemies, cults of Eldritch Abomination obtain Lovecraftian Superpower or a shaman uses a forbidden curse in the vain hopes that it keeps his people from being wiped out. Whatever the reasons behind it, the human use of disease-based magic is always seen as an evil act for the sheer amount of suffering it can bring about.
Mystical Plagues need not be limited to just attacking the physical being of those who contract it, and thus are not limited to the standard vectors of transmission of common illnesses. A curse may be designed to infect the spiritual essence of a creature, or even to only infect other magic users as they cast spells of their own. While this versatility may seem to make a magically created plague more reliable than other types, it is still not uncommon for the caster who created it to be killed as well, either directly by being infected themselves, or in the aftermath that the disease's spread causes.
A subtrope of The Plague. Compare Synthetic Plague, The Virus, and Depopulation Bomb. Can overlap with Fisher King, in cases where the Mystical Plague is caused by the actions of a kingdom's ruler. May also overlap with Maybe Magic, Maybe Mundane, or In Mysterious Ways, if the exact cause of the problem is either not understood or not explicitly stated.
- JoJo's Bizarre Adventure: It's stated at the beginning of Stardust Crusaders that only the strong-willed can control their Stands, and those lacking the proper Heroic Resolve develop a fever that will kill them, the latter happening to Jotaro's mother Holly and Josuke prior to the events of Diamond is Unbreakable.
- In King of Thorn, "Medusa" is a disease that came from a meteorite; spreading across the globe and turning most humans into statues (and others into monsters). It's revealed to have a psychic vector; rather than a viral or bacterial one.
- One Piece: Doc Q of the Blackbeard Pirates is revealed to have eaten a Devil Fruit that gives him the ability to create and spread diseases of which are of the more fantastical variety
- Tweeny Witches: As the light of the Sanctuary is fading away, a nameless disease begins to afflict the witches, leaving its victims powerless and bedridden.
- In the Captain Marvel (Marvel Comics) title starring Genis-Vell, an offhand comment by the narration states that the Black Plague was caused by the anguished scream of a Cosmic Entity.
- Star Wars Legends:
- Star Wars (Marvel 1977) has the Crimson Forever, whose name is rather contrived — "D-dead! Everyone on board, Commander! Most of them fallen at their stations... their entire bodies turned that terrible crimson...! Even their eyes...! All open... staring... like they were looking straight on into forever...!" Luke and a squadron of pilots immediately put on masks and set up quarantine but still fell ill themselves after one of them found a red gem. It turned out there were two such gems, life-forms from beyond this galaxy who were mates, and who reacted to being separated by radiating anguish that manifested as illness and dropped people into comas deep enough that even the best medical tech was fooled. The shock of seeming to contract such a disease made most people die for real, but since Luke had had a fever-dream that gave him insights on what to do, he revived when the gems were reunited.
- Knights of the Old Republic: The rakghoul disease is really the continuing spell from an ancient Sith sorcerer who used it to create an army of slaves who could function as skilled warriors and pilots, but were otherwise mindless. It's still around because it's spread by bite.
- Chasing Dragons: As the Fourth Slave War breaks out between the Abolitionist Alliance and the Valyrian League, Arthur Dayne employs a warlock to unleash a magically enhanced plague on King's Landing to keep Westeros too distracted to potentially join the war on the Alliance's side.
- The Rigel Black Chronicles draws on its source material for the Sleeping Plague, but it works quite differently and has different aims. It's not meant to kill anyone, just render a large number of children comatose and cause a public relations disaster for Dumbledore, weakening his political influence so that Riddle can push legislation through.
- In the universe of The Last Witch Hunter, The Black Death isn't a natural disease, but a magical plague created by the Witch Queen as her take on Apocalypse How.
- In the prologue of The Mummy (1999), for his crimes, Imhotep is mummified alive and subjected to a curse so terrible that it was never used on any other man. As a side effect of the curse, among the powers Imhotep would gain if he's resurrected would be the ability to bring forth the Ten Plagues.
- Seen in Oedipus Rex, being an adaptation of Oedipus the King (see Theatre below). After Thebes suffers a terrible plague, Oedipus asks a seer why the gods are punishing his people. He gets the unwelcome answer that it's his fault, as punishment for killing his father and marrying his mother.
- In Undead or Alive, the "White Man's Curse" that causes its wild-west era victims to rise from the dead and hunger for human brains is revealed to be a spell cast by the medicine man Geronimo before his death at the hands of the U.S. Army.
- The Age of Misrule: In The Queen of Sinister, magic has come back, technology has failed, and there is something lurking beyond even the mystical otherworlds of the dead and the gods that kinda, sorta, wants to destroy humanity utterly. A mystical plague that kills human life essence itself (basically 100% fatal, and dissolves its victims flesh leaving them just a load of pus inside a bag of skin and since it comes from the otherworld there is no known vector, source, or cure for the disease) is the chosen tool for this book. Too bad for it that two of the early victims were the son and husband of a woman that is an unknowing mystical champion of humanity, and the plague which was supposed to destroy her wakes that mystical potential. Nice Job Fixing It, Villain.
- Angel Mage: The country of Ystara is destroyed by one of these, the Ash Blood plague, which as the name implies turns the blood of the afflicted to ash. One third of the victims instead turn into monsters called "beastlings".
- The Burning Kingdoms: The rot is a mysterious disease that affects both crops and humans, turning them tree-like over time. In humans, this means they start turning partly to wood and leaves, which eventually kills them unless arrested by those with power over plants. Sacred wood also can slow but not stop it, so sufferers that can wear beads of this.
- Circle of Magic: Briar's Book (or The Healing in the Vine, depending on where you live) features one called the Blue Pox. Rather than being created deliberately, it's caused accidentally by improper disposal of magical potions.
- The Crimson Shadow: Greensparrow created a plague by magic to devastate Eriador so he could conquer it more easily.
- In the Cronus Chronicles, one of our heroes, a British public school student named Zee, is sent to America to get away from one of these, not realizing he is in fact the carrier.
- Dark Shores: The blight from Dark Skies is first shown as foul-smelling rivers of black goo flowing through the countryside but then it turns out that any closer contact with it turns living beings into zombie-like creatures, devoid of any rational thought and (according to Grand Master Quindor) any life.
- In A Day of Fallen Night (prequel to The Priory of the Orange Tree, below), we see the first emergence of the draconic plague — only nobody knows what it is yet. It first appears in Hróth and begins with unusual redness in the fingers that spreads up the arms, eventually causing an unbearable burning sensation, violent madness, and death. Despite efforts to contain it, poor sanitation practices coupled with the spread by draconic creatures result in it spreading to locations worldwide. It is termed as "the burning" by some due to its symptoms.
- In The Divine Comedy, falsifiers (which include alchemists, perjurers and counterfeiters) are punished in the last bolgia in the 8th circle of hell by being afflicted by horrible diseases.
- The Dresden Files claims that The Black Death was originally created by Fallen Angels through magic. The book Death Masks centers on Harry recovering a religious artifact before the Fallen can use it to create another plague.
- Elemental Masters: In Phoenix and Ashes, Alison summons a disease elemental and sets it loose; it's implied that this caused the 1918 H1N1 pandemic.
- In the Emberverse novels, contact with the bodily fluids of a follower of the Church Universal and Triumphant can cause these in the form of necrotic lesions, the pus from which is outright poisonous. It gets to the point that objects that have touched captured CUT adherents are routinely burned as a precaution. Even swords.
- The Hands of the Emperor: Whatever befell the island of Woodlark some time after the Fall. Whoever was affected died and turned into a monster. In the end, the island was quarantined and, to ensure the plague couldn't spread, the emperor burnt it down to the bedrock.
- In the Harry Potter series, there is a great deal of fear of werewolves due to misinformation and concern about the spread of Lycanthropy, a parallel to AIDS, which sufferers of are discriminated against. In Prisoner of Azkaban, Lupin resigns after Snape outs him, and in Order of the Phoenix, it is revealed that Lupin and Sirius already despise Umbridge due to some anti-werewolf legislation she wrote up that makes it near impossible for werewolves to find employment.
- In the Labyrinths of Echo series, Anavuayna is an ancient magic plague, borne out of the curse of an enraged Elven princess, that not only slowly liquifies the victim's body, bones and all, while the victim is fully conscious, but also destroys their soul on every level of existence.
- In A Practical Guide to Evil, villains are infamous for sometimes using- or at least trying to use- magical plagues.
- Warlock, when faced with a revolutionary army which includes cavalry, proposes to unleash a plague on the horses- he has one lying around in his laboratory. Also, he is the creator of several other doomsday works, some of which could be plagues.
- The Dead King uses plagues that kill and zombify all the infected.
- The heroes too: at one point the Grey Pilgrim engineers and uses a plague that kills roughtly 3000 people to catch the Black Knight.
- In The Priory of the Orange Tree, fear of the draconic plague is the reason for Seiiki's laws against almost any immigration (save for a few Mentish traders restricted to one port city). It runs rampant in Yscalin following the king's conversion to wyrm-worship. Loth has to deliberately infect himself to escape the country with a piece of vital information and experiences the unpleasant symptoms: reddening hands, fever that escalates to a burning sensation, and malaise. Fortunately, he reaches his destination — which has a cure — in time.
- The Riftwar Cycle: In The King's Buccaneer, the Overlord of the City of the Serpent River works with some Pantathian serpent priests to kidnap a couple of hundred people from the Kingdom, mostly women and girls. Then they create magical duplicates of the prisoners and infect the duplicates with a magically created plague that is spread by contact and is almost always fatal. Then they send the prisoners back to the Kingdom, to the Western Realm's capital city of Krondor.
- In The Sister Verse and the Talons of Ruin, this is what people think is initially happening, until the plague refuses to spread, and they realize that it's a conscious entity possessing people.
- The Song of the Lioness quartet has one early on: the Sweating Sickness is sent by an evil duke in hopes that it will weaken the kingdom and kill everyone who stands in his way to the throne.
- Sweet & Bitter Magic: Dark witches have unleashed ones twice by the time of the story. In the second case, it leeches away people's memories and joys, leaving them empty shells, before their bodies wither away too until they die. The second plague turns out to be the accidental side effect from the dark magic being used, not a deliberately inflicted one.
- In the Sword of Truth book Temple of the Winds, the Imperial Order unleashes a plague, based on The Black Death and made much worse by magic, on the heroes' capital city. For bonus Kick the Dog points, Emperor Jagang deliberately infects a group of young children as patients zero.
- Tolkien's Legendarium:
- The Silmarillion mentions a plague apparently sent by Sauron to weaken Gondor so he could regain control of Mordor.
And in the days of Telemnar, the third and twentieth of the line of Meneldil, a plague came upon dark winds out of the east, and it smote the King and his children, and many of the people of Gondor perished. Then the forts on the borders of Mordor were deserted, and Minas Ithil was emptied of its people; and evil entered again into the Black Land secretly, and the ashes of Gorgoroth were stirred as by a cold wind, for dark shapes gathered there.
- A mystical plague is used in the same work to account for the death of Túrin Turambar's younger sister Lalaith.
- The Silmarillion mentions a plague apparently sent by Sauron to weaken Gondor so he could regain control of Mordor.
- The Tough Guide to Fantasyland: Natural plague is unknown (possibly due to a lack of bacteria or viruses). Magical plagues though are common tools of the Dark Lord and his minions. Due to this, it isn't caught by those not specifically targeted (like the protagonists).
- In The Traitor Son Cycle, the Big Bad crafts a curse that spreads and behaves like a deadly disease. It manages to scour two countries before a cure (also magical) is found.
- The plot driver in The Legend of Dick and Dom; the heroes are collecting Plot Coupons to make a magic potion to cure a plague. They discover in season two that it was magic, caused by the Big Bad.
- The Lord of the Rings: The Rings of Power: The Southlands are affected by a mysterious black goo that sickens the vegetation and the animals. Several episodes later Lindon also is affected by this black goo.
- Twice in Merlin (2008):
- In the first season, Nimueh puts a creature into the water supply that sickens everyone in Camelot.
- Later, a magical creature called a Lamia sickens an entire village AND the knights who go with Merlin when he is sent to try and stop it.
- The Psi Factor episode "Death at Sunset" deals with an inexplicable disease which kills the inhabitants of a small town one by one.
- Supernatural: The Croatoan Virus, which turns people into rage-filled zombies, is demonic in origin. Specifically, it was developed by the Horseman Pestilence on Lucifer's orders in order to herald the Apocalypse.
- The Twilight Zone (1985): In "Many, Many Monkeys", Jean Reed speculates that she and everyone else afflicted with the plague of blindness are being punished because they have become monkeys who see, hear and speak no evil. She thinks that nature has turned a blind eye to humans because of their diminished humanity. Although Nurse Claire Hendricks initially dismisses this idea as preposterous, she later becomes convinced that Jean is correct, even after the government links the plague to the accidental release of bacteria.
- Alien Weaponry's "Urutaa" (literally "plague" in Māori) speaks of the epidemic that broke out among the Māori-speaking Ngati Uru tribe after an 1808 visit by the brig Commerce commanded by James Ceroni, which they believed was a curse placed on them by Ceroni after he accidentally dropped his pocketwatch in the harbor.
- In the Book of Exodus, a couple of the Plagues of Egypt, which God called to force the Pharaoh to free his Jewish slaves, count: the plague of pestilence (which only affected livestock) and the plague of boils (skin disease).
- In Classical Mythology, Miasma (as referenced in the Oedipus the King example below) was a part of the ancient Greek's cosmological view: if a people or their ruler acted in a way that defied the natural order (as they saw it), this was a logical consequence of said actions.
- In Mesopotamian Mythology, when Inanna realizes she's been raped in her sleep her wrath unleashes horrible plagues on Earth, plagues that continue until she tracks down the rapist and kills him. In a variant, it's implied it was an accident, caused by Inanna simply becoming just that angry, and that the plagues ended once she realized what she had done and cleaned up her mess.
- In Pacific Mythology, the normally-benevolent Poli'ahu inflicted her ex-fiancé Aiwohikupua and his lover Poli'ahu's sister, Pele with chills and fever because they snuck off together on what would have been Aiwohikupua and Poli'ahu's wedding day.
- If angered sufficiently, the vicious Scottish fae Nuckelavee could infect horses, crops, and humans with a disease called Mortasheen.
- One rise scenario from All Flesh Must Be Eaten has the PHADE virus, which is the zombie plague... as an STD. The whole thing started when a guy was so bereaved about the loss of his girlfriend, he used necromancy to bring her back for one last fling. And then he decided he wasn't that into her, and slept with someone else, and it just spread from there.
- Ars Magica: The spell "Curse of the Unportended Plague" starts a plague in a city over a period of 6-12 months. It will kill 10% of the city's population over a period of a few months.
- Dungeons & Dragons:
- The Judges Guild adventure "Verbosh" had a new spell called "Plague" which causes 20-70% of the population in a 1 mile square area to be incapacitated for 1-4 weeks as well as killing many of them.
- The 2E supplement Tome of Magic. The 7th level priest spell Breath of Death (reversed Breath of Life) affects an entire community. Anyone who fails a saving throw vs. death magic is infected with a disease that is fatal in 1-6 weeks.
- Exalted features, among many others, the Great Contagion. Dug out of a dimensional nexus that instills insanity in all those who view it without proper protection by one of the Deathlords, it killed about 90% of Creation on the first go. To clarify; not 90% of Creation's people, 90% of everything. Plants, animals, spirits, gods... anything that could basically constitute "alive" in Creation was fair game. On top of that, the disease was so infectious that mystically observing it was capable of contracting it. The only thing that stopped it from finishing the job was one of the other Deathlords inviting The Fair Folk in to finish the job; the chaotic energies of the Wyld that came with the invasion actually bolstered the immunities of the survivors.
- Magic: The Gathering has the disease Phyresis, spread via contact with Glistening Oil. The oil inevitably changes any organic life it encounters into Phyrexians, biomechanical monsters one card refers to as "An amalgam of living metal and dead flesh." Symptoms include the destruction of the patient's soul, snuffing their Planeswalker Spark (if they had one) and religious fervor over spreading the perfection of the oil far and wide. It gets worse. Phyrexians produce more oil, and so even a single drop can Doom an entire world (and, canonically, did doom the plane of Mirrodin). As an added bonus, Phyrexians dabble in the creation of mundane plagues to target specific populations, as shown off in the cards Spreading Plague, Engineered Plague, and Plague Engineer.
- In Warhammer and Warhammer 40,000, cultists of the Plague God Nurgle are granted powers to create and spread disease. The most feared among them is Nurgle's Rot, which has no consistent symptoms, can't be cured by natural means, and is said to consume the souls of the afflicted.
- This is shown in Oedipus the King: Oedipus's actions (killing his father, marrying his mother) unknowingly bring blight and plague ("miasma") to his people. Crops do not grow, stock animals die off, and women suffer from infertility, all because Oedipus's actions went against classical concepts of morality.
- BIONICLE: The Dreaming Plague, caused by Annona, a being that feasts on dreams. Its victims lose the ability to dream, slowly turning them violent, insane, and ultimately dead. It almost wiped out the Iron Tribe, and the handful of survivors were shunned by all the other tribes for fear of carrying the disease.
- ANNO: Mutationem: In the past, the world underwent a crisis when the Mechanika Virus caused bodies of people to be turned metallic. Later on, the virus' origin is stated to be from Limen, an Eldritch Location that also brought dangerous phenomena which spread out into the world.
- In Bloodborne, the Scourge of the Beast is a plague which transforms people into werewolf-like creatures called Beasts. The twist is that the organization that's supposedly combating the Scourge, the Healing Church, is actually the cause of said plague, and that their supposed panacea blood ministration (as blood of a Great One) causes people to turn into beasts.
- Darkest Dungeon: The Crimson Curse is a debilitating infection that has two mystic properties; it cures every other disease, and it can't be cured unless a Courtyard boss is killed. The cutscenes make it clear that the infection is supernaturally tied to both the Vampire Countess and the Final Boss.
- In Dishonored, the rat plague initially was a virulent plague that the Spymaster brought from the Pandyssian Continent to wipe out the poor in Dunwall. Granny Rags seems to spread the plague by summoning more and more rats to areas. You can too if you go the High Chaos route.
- The Blight disease spread by the Darkspawn in Dragon Age is said to be a curse by the Maker upon the Tevinter Magisters, who turned into the first Darkspawn themselves under its influence. It twists and eventually kills everything infected by it. The sites of especially large darkspawn raids have been hit so hard that dead bodies won't rot because all insects and bacteria have already been killed.
- In the Dragon Age: Origins DLC "Warden's Keep", Avernus' research into the Taint suggests that it's alien to Thedas, with its true origins unknown even to the denizens of the Fade, such as Spirits and Demons. Avernus believes that the key to understanding it is tied into whatever caused the corruption of the Black City.
- Dragon Age: Inquisition reveals that Red Lyrium is lyrium tainted by the Blight. This has disturbing implications: since the Blight only affects living things, lyrium is alive, meaning using it is just another form of Blood Magic. The fact that Red Lyrium is found in the Primeval Thaig, which predates the First Blight, hints that the Blight existed long before the Darkspawn appeared. It didn't start with them.
- Elden Ring has the Scarlet Rot, a horrifying pathogen with few cures (most of which boil down to "apply fire to affected area and hope everything else can survive without it") that causes the infected to rot alive and have Alien Kudzu grow on their bodies. And it can affect anything: Humans, animals, plants, dragons, crystalians (aliens who, as their name suggests, are made of stone), the soil, the sky, minds, and even metaphysical concepts like Great Runes. Gameplay suggests that the only things immune to the rot are fantasy robots and things that aren't really there in the first place (such as projections like Golden Shade Godfrey). The reason why the Rot is so unstoppable is because it's a manifestation of an Outer God sealed in the Lake of Rot, and the Demigod Malenia is its chosen one and Patient Zero. Luckily for the rest of the world, Malenia is such a determinator that she can contain the Rot within her own body with sheer willpower. Unluckily, she's been resisting it for so long without any rest that said willpower is seriously fraying, and even her best efforts can't stop her from being a Walking Wasteland on a good day.
- The Elder Scrolls:
- In the series backstory, the Thrassian Plague ravaged Tamriel in the 1st Era. Created by the "slug-men" Sload of Thras, the "coral kingdom" to the southwest of Tamriel, who are known to excel as necromancers and Evil Sorcerers. The Thrassian Plague killed more than half of Tamriel's population. In response, the nations of Tamriel formed the All-Flags Navy, which ravaged Thras, killed all of the Sload it could find, and finally sunk Thras beneath the sea. (The Sload survived, and would raise Thras to the surface once again, but never again tried something as ambitious as the Thrassian Plague) Unsurprisingly, Peryite, the Daedric Prince of Pestilence and Tasks, is rumored to have been associated with the creation of the plague.
- Also from the backstory, the Knahaten Flu ravaged Tamriel in the 2nd Era for a period of about 40 years. It is attributed to an Argonian shaman who created the plague by manipulating the spores of the Hist in retaliation for the awful treatment of his people by the other races. Other sources claim that it was a natural disease, but the general distrust of the Argonians throughout Tamriel combined with the fact that Argonians were immune to the disease made the "Argonians caused it" story more popular. The Flu is believed to have completely wiped out the Lilmothiit "Fox Folk" and the Kothringi silver-skinned menfolk, both formerly native to the Black Marsh.
- Dagoth Ur's Blight, which spreads via Blight Storms and his minions. It can inflict crippling blight diseases and, most importantly, the Corprus Disease. The Corprus Disease is actually a curse of Dagoth Ur's (essentially divinity channeled from the Heart of Lorkhan), which brings those inflicted under his influence. It brings with it a nasty case of Body Horror and deteriorating mental functions.
- The Crimson Plague in Tribunal is not a standard disease, but a mystical one spread by the powerful lich Gedna Relvel. You'll need to kill her in order to stop it, and it's no easy task.
- In Skyrim, Peryite's Daedric quest involves hunting down and killing the leader of a group of his rogue followers who've been inflicted with such a plague. Before going rogue, Peryite intended to have these followers spread a this plague to "cover the world" with his "blessing".
- Heretic 2 has a mystic plague as a central part of the story, which was unleashed as D'Sparil's Dying Curse from the end of the first game. Mostly it causes death, insanity and violence, but there is mention of another version that can be used to control people.
- Hollow Knight: The main threat in the game is a mysterious, terrifying plague that’s turning Hallownest into a Death World. Bugs afflicted with it are driven to violent insanity by it and get reanimated as monstrous husks after dying. It was created by the Radiance, the god who created bugkind, as a "divine" punishment after they stopped worshiping her and your character is an Empty Shell created to try and contain it.
- At the start of Neverwinter Nights, Neverwinter is in the grip of one of these. Curing it requires body parts from four magical creatures shipped from Waterdeep. Which are promptly stolen by the group behind the plague after they arrive, forcing the Player Character to spend the first chapter recovering them.
- Octopath Traveler II: Trousseau concocted a deadly poison with the help of the Shadow and released it into the air above Healeaks to wipe out its entire population as part of his plan to "save" humanity by killing everyone. In Castti's final chapter, he strikes again, but Castti is able to create a cure and save those who got infected after having to kill Trousseau.
- Ōkami: When you arrive at Sei-An City, you find the citizens all seriously ill from a disease that seems to be originating from a thick green mist covering the city. Worse, the queen seems to be doing absolutely nothing to help. It's caused by a demon who has possessed the emperor, infecting him with some sort of illness and leaving him bedridden as he exhales the infectious mist.
- In Overlord II, the plague was caused by an event known as the Cataclysm that devastated the lands of the first game and gave rise to the Anti-Magical Faction. The ending reveals that the plague was caused by Florian Greenheart, an elf born without magic who tampered with the Tower Heart in an attempt to gain magical powers. With the help of Rose, he then created the Glorious Empire through the anti-magic sentiment of the humans following the Cataclysm while secretly gathering magic himself.
- In the backstory of NieR, the sudden appearance of a large white humanoid figure and a dragon in Tokyo's Shinjuku District causes a disease called "White Chlorination Syndrome" to appear. This disease, which either turns humans into mindless monsters, or pillars of salt, sends humanity to near extinction, and the events of the game happen thousands of years after this.
- The Filth of The Secret World. Essentially the Dreamers' will to awaken made manifest through their reality-warping powers, it exists to corrupt any being it touches and convert them into a subservient mutant dedicated to releasing the Dreamers from captivity (which would cause a Dream Apocalypse). For good measure, it takes a variety of forms throughout the setting: along with its common "tentacled black ooze" form, it also appears as toxic gas, weird weather, eldritch graffiti, radio signals... and according to Dr Klein, the historical epidemic popularly known as the Black Death.
- The Delphinus Parasite in Shin Megami Tensei: Strange Journey doubles as this and a Hate Plague. It's actually the inchoate form of the resident Demon Lord's soul.
- The King of Death in Tears to Tiara 2 summons a plague, clearly based on The Black Death based on the graphics, that devastates Northern Hispania before being checked. And it continued to spread within The Empire, the very side that summoned it.
- Trauma Center: Implied in Trauma Team, despite the developers otherwise trying to up the realism compared to previous games. The Rosalia Virus causes insanity via tumors in the brain, but oddly, two people infected know the name Rosalia, the name of the original carrier (who suffered none of the symptoms), before the disease was named or Rosalia's connection was even known. Also, Rosalia herself appears as a ghost to her childhood friend, and her last words imply that she knew her death would lead to the pandemic in the last part of the game.
- Vampire: The Masquerade - Bloodlines: A deadly disease spreading through vulnerable people in Los Angeles turns out to be the creation of a vampire Apocalypse Cult who cultivate it within their bodies.
- The plague of undeath that turns people into zombies in Warcraft III, preparing the way for a demonic invasion.
- The "Severed" elves in Inverloch, so termed because they lack the connection with the spirits that grants magic and immortality. When more and more elves began to be born with the signs (white hair and gold eyes), the elves began to exile them starting at the age of twelve in hopes that it would prevent the affliction from spreading. It only made matters worse, leading to speculation from the exiles that it was a punishment inflicted by the spirits for the elves' arrogance and isolationism. They prove to be right.
- Stand Still, Stay Silent: The "rash illness" turns its victims into horrific monsters. It is strongly implied to be connected to the resurgence of magic. In fact, the old world actually managed to cure the disease without too much trouble. It's just that wasn't enough to actually save anyone, because the mundane disease was merely the vector for the mystical one. People who took the cure did not mutate into monsters, but still inevitably suffered brain death, and then their spirits stuck around as angry ghosts.
- In Unsounded, regions in the nation of Alderode are afflicted by the Weeping Plague, which somehow spreads by making eye contact with a sufferer.
- In The Gamer's Alliance, the Blood Fever is a disease that is fatal to elves as it eats their blood cells from within and makes blood erupt from their bodies in the later stages. At first it seems like a natural plague, but over time and some investigations later it becomes apparent that the plague may in fact have a magical origin and has been created for a special purpose in which elven demise plays a part.
- SCP Foundation: Most SCPs with the "infectious" tag fall under this.
- There are several diseases that are spread not though any physical vector but are instead spread though information, which are known as memetic hazards. One example of this is a key. If you learn anything about what the key looks like you are infected one of three things will happen. You will kill yourself at the first opportunity and anybody who sees you die is infected, or you will go on a murderous rampage and anybody who sees your victims die is infected and after killing enough victims you will disappear and infect anybody who hears what you say right before or you will become strangely happy and will be driven to infect other people by sharing information about the key even if you weren't directly infected by the key and after infecting enough people you will disappear and temporarily leave behind an area that causes anybody who enters it to be infected.
- There also are plenty of more normal diseases that simply have weird effects on people that are infected with them such as a disease that causes you to regurgitate useful objects when you need them or a herpes virus that causes you to hallucinate that you are trapped in a game of Skyrim whenever you have an orgasm.
- A straighter example of this is SCP-217 ("The Clockwork Virus"), a virus that turns living things into clockwork, which is believed to be the breath of God by a cult of machine-worshipers.
- The Astral Plague in Tales From My D&D Campaign isn't a disease in the most technical sense of the word, as it doesn't seem to be contagious. Caused by exposure to the astral radiation from active Ytarran Teleportation Portals, the Plague wiped out the entire Ytarran race within a generation. More recently, the heroes have become infected, though they are at present shielded from the effects by a friendly spirit. However, the protection won't last forever, and the party will eventually need a cure.
- Family Guy: In "If I'm Dyin', I'm Lyin'", Peter claims to have healed Chris of a disease he made up, which convinces the town that he's a divine healer, and he milks their worship of him for all it's worth. However, this makes God smite the Griffins with plagues based on those He cast upon Egypt, including darkness (the light bulbs going out), gadflies (Brian getting fleas), boils (Chris getting acne) and blood (Stewie's bath water turning to blood).
- Implicitly in the Justice League episode "Fury", in which a rogue Amazon named Aresia unleashes a global plague that only affects men, even alien men like J'onn and Superman.
- In one episode of The Smurfs (1981), Gargamel's Evil Plan is to spread a magical disease called the hopping cough, which causes a cough that makes the victims jump violently. (The idea is that if the Smurfs contract it, he can find and catch them more easily — or, in the non-Bowdlerised version, the illness is simply fatal if left untreated.) He even shows some smarts this time and plans to ambush them at the places where the ingredients for a cure can be found. Unfortunately for Gargamel, he eventually catches it himself while looking for them, and Papa Smurf does indeed manage to make the cure.
- Trollhunters: Claire contracts a nasty cold in the Season Two finale; coughing, sneezing, and Exhausted Eye Bags from overuse of her staff.
- In the Visionaries episode "Horn of Unicorn, Claw of Dragon", a Magical Plague strikes Prysmos, affecting all but one of the Spectral Knights and up to five of the Darkling Lords. In this case, the precise cause of the Plague is unspecified, though Merklynn does say that he foresaw it coming and tried (unsuccessfully) to send the Darkling Lords on a quest for the ingredients (the unicorn's horn and dragon's claw referred to in the title) needed for a healing spell.