Look on my toys, ye Mighty, and despair!
Santa Claus is an unusual man, ain't he? He's a spaceless, timeless immortal male senior citizen that seems to change his name and ethnicity depending on whatever country he exists in. He is omniscient (how else would he know if you've been bad or good?) and omnipresent (he can drop the right selection of gifts in every house on the planet with no one ever seeing him despite being a fat man apparently getting in through the chimney) and he can survive things that should kill a normal man his age (eating everybody's cookies and milk, living in the inhospitable wastes of the Northern hemisphere, nearly getting shot down by the U.S. military every year for being an unregistered airborne entity, etc).
Often times this trope applies to Santa if it involves less the Christian side of Christmas (that is unless Yahweh is more the eldritch-horror type unsurprisingly) and more with the various Pagan traditions that applies to the holiday, various rituals of protection that have long since lost their original purpose over the years and have become modern Christmas traditions, meaning that the The Fundamentalists were right and Santa is a Pagan idol that could possibly destroy the Earth. Children don't give him milk and cookies as a "please and thank you" for the presents; they are offerings to appease his ever slumbering rage, waiting for the day when he reigns jolly doom upon the world.
Now the kind of Eldritch Abomination would depend on the kind of traditions that would placate him. As a Humanoid Abomination, it is pretty much self-explanatory. The fact that he is able to survive whatever diabetic coma that keeps him away the other 364 days of the year speaks for itself. As an Animalistic Abomination, he does not have flying reindeer pull the sleigh, he is the flying reindeer, or at least some kind of Yule-Goat commonly confused for his more malicious counterpart. As a Botanical Abomination, Christmas trees can act as an effigy in its likeness, the various Christmas ornaments his many eyes or eggs or something.
- Dragon Ball Z Abridged: In the abridged version of Plan to Eradicate The Saiyans, re-titled to Plan To Eradicate Christmas, Doctor Raichi and Hatchiyak are adapted as being Santa Claus, who has grown fed up with all the naughtiness in the world and decides to destroy the Earth. The main cast also refers to Santa's second form (being Hatchiyak) as Super Santa.
- Sword Art Online Abridged: Kirito fights a giant evil Santa called Nicholas the Renegade for the Christmas event, following a rumor that it drops an item that can resurrect a dead player. It's a hat.
- In the "definitive Lord of the Rings e-text", the Balrog is also Santa.
The shadow-thing burst into fire as it landed and yet remained unharmed. Its streaming mane of snow-white locks kindled and blazed behind it. In its right hand it held a sword, like a stabbing tongue of fire; in its left it held a whip of many thongs. The thing was garbed all in red velvet and about its head was a floppy red hat. Upon its feet were two smoldering pink slippers.
- In the Finnish Dark Fantasy Horror film Rare Exports: A Christmas Tale, Joulupukki (the Finnish equivalent of Santa Claus) is portrayed as a massive goat-like entity comparable to The Krampus frozen in a massive block of ice, having long since been imprisoned in Korvatunturi by the Saami people. It is served by a race of Humanoid Abominations that all look like identical skinny, bearded old men that are its Christmas Elves, who are implied to have been ordinary people before being turned into identical Ambiguously Human minions.
- The Dutch horror movie Sint involves a man discovering the hard way that Sinterklaas is the ghost of a psychotic Knight Templar who reappears alongside his army every thirty-five years to inflict mass murder on cities and towns. While the heroes manage to give the ghost a bloody nose this time, its all but flat out stated that it didnt stop him.
There is a song about him. It begins: "You'd better watch out..."
- Soul Music offhandedly mentions the Hogfather, the local Santa Claus equivalent who goes around giving gifts of meat to good children, and bags of bloody bones to bad children.
- Hogfather uses him as a central figure (or rather the central victim of the Auditors' plots). It turns out that his sleigh is drawn by massive boars instead of cute little pigs and he lives in a castle made entirely of bones, and started out as a human king sacrificed to ensure the winter would end soon.
- A post-game sidequest in BoxxyQuest: The Gathering Storm features "The Spirit of CTH'RISTMAS," an unholy fusion of Santa's cap and Cthulhu that shows up out of nowhere to attack a shopping mall during its annual holiday sale. Afterwards, the locals are just as confused about the whole ordeal as you are.
Shopper: I think we've learned a valuable lesson here today. I just wish someone could tell me what it is. Something about commercialism, maybe?
- In Cookie Clicker, Santa was introduced in the Christmas update, appearing in an icon in the corner. It starts off as a Festive test tube, before becoming holiday decorations (tree ornament, wreath Christmas tree) becoming elf (from a fetus to old age), to the actual Santa Claus before it evolves into an Eldritch Abomination of unfathomable horror. Though apart from the change in appearance, he continues to act as he always did.
- Surreal gothic browser game Fallen London has Mr. Sacks, aka "The Crimson Beast of Winter", a hooded, faceless, only vaguely Humanoid Abomination who appears every December. He doesn't give people gifts; the people of London are instead supposed to give gifts to him. He accepts anything from abstract things like your "best regards", to fine wines, to parts of your body... or even you, if you're foolish enough not to have anything else to offer. But something of yours WILL end up in his sack. And unlike Santa, he doesn't just appear on the Christmas eve. No, Mr. Sacks visits you on each of the twelve days before Christmas. And he expects a gift with each visit. In the Spin-Off game Sunless Sea, your captain may be called upon to perform three deliveries for Mr. Sacks. Refusing him is implied to be bad for your long-term well-being. Accepting is likewise likely to be bad for you short-term. Accepting and taking too long with it is likely to be the worst (and last) idea you'll ever have.
- In Belzebubs, Satan Claus/Father Antichristmas is a strange, demonic creature that visits the Belzebub's household every year. Leviathan thinks that he is just their dad in a costume since his dad is always conveniently out... only when he removes the goat-skull mask just as their dad walks in, he goes into a homicidal rage, forcing them to behead Satan Claus with an axe.
Satan Claus: .oH oH oH
- SCP-4666 "The Yule Man" from SCP Foundation is a particularly sadistic Humanoid Abomination that acts as a grotesque parody of The Krampus and Bad Santa. It sneaks into people's houses and proceeds to torture the families there in gruesome, unimaginable ways before it kills them. In most cases, it will leave one of the children alive, kidnapping them and forcing them to make toys from human remains, with the toys being given to one of the families it haunts 15% of the time instead of the torture and murder. If its child slave does not fulfill the proper quota of toys, it will either eat them, torture them or use their body parts as materials to make more toys.
- This short disturbing animation by Cyriak, also an example of Animalistic Abomination.
- The in-universe equivalent to Santa Claus from Chowder is Knish Kringle, a caterpillar-esque creature that travels around the world Knishmas night. He comes down a chimney and if the Shmingerbread House (a life-size gingerbread house) left for him tastes good, he'll regurgitate gifts for the owners. If he doesn't like it, he'll go into an Unstoppable Rage and destroy the house.
- In the Invader Zim Christmas Episode "The Most Horrible X-mas Ever", Zim downloaded all Christmas and Santa knowledge into a gel-based Santa suit as a means of disguising himself as the titular Santa as a plot to conquer Earth. Unfortunately, A.I. Is a Crapshoot and the suit slowly starts to take control whenever something especially Christmasy happens (like children asking for hugs or when GIR starts singing Christmas songs). Zim manages to free himself of the suit before it grows into a monster, with Dib banishing it into space. In the distant future, it is revealed that the Santa suit is not only still alive, but it returns every Christmas to wreak havoc, cities since having been enclosed in protective domes with giant milk and cookies left to placate its rage.
- Rick and Morty introduces the disturbing Mr. Chimney in the spin-off comics. He's a strange, man-shaped creature with dozens of insectoid legs who sees and knows everything, eats lost teenage boys, and isn't allowed within 100 feet of a school.
- In the Space Ghost Coast to Coast episode "Girl Hair," Space Ghost ends up killing Hanson so they can't snitch on him after he runs over the Tooth Fairy in his spaceship (It Makes Just As Much Sense In Context). Later he's spooked when Santa appears at Ghost Planet and expects to be chewed out, only to be surprised when Santa declares that Space Ghost is a very good boy for killing the Tooth Fairy, because "I've been trying to kill her myself for years!"
Moltar: But... why, Santa, why?
Santa: So that I could be the Tooth Fairy, Moltar! Then Santa could use all the little children's teeth to make bizarre and twisted toys for Santa's own amusement. Hohohohoho!
Space Ghost: (thinking) That doesn't sound like the Santa I know...
"Santa": That's because I'm not the Santa you know, Space Ghost! I'm Bizarro Santa, from the Electroid Dimension! (transforms into a screaming pile of flesh, claws and teeth)