Animalistic Abomination

A sub-type of Eldritch Abomination, the Animalistic Abomination is a monstrosity that resembles one animal - or often multiple - and that resemblance can range from "significant enough to recognize" to "disturbingly accurate", while still remaining definitely "alien" on the Sliding Scale of Anthropomorphism. However, just because an abomination has an animal's guise doesn't remotely restrict it to an animal's intelligence.

This type can be even more nightmarish than your average horror, due to the contrast of something so thoroughly and decidedly unnatural appearing in a form "borne" of nature. Somewhat less commonly, Animalistic Abominations may actually be a direct product of their environment, which can sometimes suggest that nature itself is harboring a severe animosity towards locals... assuming you're still currently on Earth, anyway.

It is somewhat easy to confuse with Starfish Aliens: these are life-forms most simply adapted to a different environment from humanity and might even take on more familiar forms for our benefit, whereas Animalistic Abominations (like any kind of Eldritch Abomination) will feel wrong and actively tamper with comprehension of it no matter how much they "should" be at home - while just as likely to use A Form You Are Comfortable With, their form being familiar is anything but a good sign for us, assuming it's even aware of humanity as a distinct group. Good candidates for such monstrous beings include various reptiles, large insects (and/or arachnids), cephalopods (if you want a nice Cthulhu-esque touch), and the abomination may even be based on at least one sufficiently-weird Seldom-Seen Species. Heck, you can even make them like actual starfish if you want!

The Worm That Walks may overlap with this, since an eldritch being may use a mass of smalls animals (or animal-like creatures) such as insects to take on a humanoid form.

Anime and Manga

 * Berserk has the Beast of Darkness, a monstrous wolf that is Guts' bloodlust and hatred of Griffith given form. It's one of the swordsman's greatest enemies, and wants nothing more than to make him submit to his darkest desires so it can permanently steal control of his body and freely indulge in its psychopathic bloodlust.
 * The Tailed Beasts of Naruto fame are dangerous monsters made of primal Chakra, and look like massive and unholy versions of otherwise ordinary animals, such as the Eight-Tails looking like a skinless ox with octopus tentacles; the Yonbi, or Four-Tails, looking like a monkey; or the Nine-Tails being a demonic-looking fox. Most have been sealed inside of human hosts in hopes of keeping the unruly beasts under control, but this often results in the hosts going insane, or else having control of their bodies ripped away by the beasts possessing them - that is, if they're not warped beyond recognition either way. All Tailed Beasts have names given to them by the Rikudo Sennin himself: Shukaku, Son Goku, and Kurama (the Kyubi) are the only ones known. And according to the Hachibi,.
 * Puella Magi Madoka Magica has.
 * In Pokémon: Jirachi—Wish Maker, the villain Butler attempts to create a Groudon using Jirachi's wish granting powers. The result is a bizarre demon that looks like Groudon, but it's pretty easy to tell it's not.

Comic Books

 * In Bone, the Big Bad of the entire story is revealed to be . Its Dragon is The Hooded One, . According to the prequel comic Rose,.

Film

 * The titular monster of John Carpenter's The Thing is first shown in the very convincing guise of a sled dog, running towards an American research station in Antarctica. When it's placed in a kennel with other dogs on-site, they immediately realize it's nothing like them and act hostile towards it, just before it transforms to attack the other dogs and absorb most of them.
 * In Annihilation, animals exposed to the Shimmer are mutated into a form that, while recognizable, are far more alien and freaky than anything found on Earth. On the more mundane side of things is an alligator with a mouth full of shark teeth, while far more extreme is a bear with its skull exposed that can mimic the dying screams of a human it killed, and has one of her eyes and quite possibly her entire skull assimilated into its being.

Literature

 * Shelob from The Lord of the Rings is a terrifying giant spider who happens to be the daughter of Ungoliant, a monstrous Eldritch Abomination that terrorized Middle Earth before Sauron rose to power. While she doesn't possess her mother's apocalyptic appetite and godlike strength, she's still one of few beings that the One Ring has no power over, and is framed by the narration as being less an animal and more a demon masquerading as one.

Oral Tradition, Folklore, Myths and Legends
"The locusts looked like horses prepared for battle. On their heads they wore something like crowns of gold, and their faces resembled human faces. Their hair was like women’s hair, and their teeth were like lions’ teeth. They had breastplates like breastplates of iron, and the sound of their wings was like the thundering of many horses and chariots rushing into battle. They had tails with stingers, like scorpions, and in their tails they had power to torment people for five months."
 * The Bible:
 * In Chapter 9 of the Book of Revelation, the first eleven verses describe "locusts" that are summoned from the Abyss, and appeared as armored horses with human faces, long hair, scorpion tails and leonine teeth. Unlike a typical Plague of Locusts, they were sent to torment and harm "those people who did not have the seal of God on their foreheads" for nearly half a year; they are also led by the angel of the Abyss (known as Abaddon in Hebrew and Apollyon, or "Destroyer", in Greek). From Revelation 9:7-10:


 * The Black Shuck of English folklore is a canine apparition that is frequently recorded as an omen of death; other legends of spectral black dogs have been linked to it in folklore. The Shuck tends to appear as a black shaggy dog of varying description, with consistent traits including fiery eyes (or perhaps eye) and its immense size. In the most notable report, the Shuck burst through the doors of a church with the sound of a thunderclap, killing two people and causing the church steeple to collapse through the roof, and then leaving scorch marks on the north door as it disappeared; the author describes it as a "black dog, or the divel in such a likenesse". Another account recorded in the Peterborough Chronicle suggests they are used as part of a Wild Hunt.

Video Games

 * Undertale has one of these in.
 * Bloodborne has many, but the Cleric Beast and Vicar Amelia are among the most iconic examples. They look like massive bipedal wolves with reindeer antlers that have been starved to death, and their screams sound truly hellish. Both seem to be some form of Wendigo, with the latter introducing herself by erupting forth from the body of a seemingly normal priestess.
 * Barbas from The Elder Scrolls is a benevolent and adorable example, being a talking Big Friendly Dog with a Brooklyn accent and the best bud of Daedric Prince Clavicus Vile... as well as an aspect and the conscience of the Prince himself, who tries to keep him from screwing over anyone unfortunate enough to bargain with him. Furthermore, The Elder Scrolls: Redguard shows that he doesn't strictly stick to the form of a dog, and can be seen randomly changing forms before resetting back to his dog form. Clavicus will even comment on it, saying that he likes being a dog on sunny days, as well as many other things.
 * Since the Heartless from Kingdom Hearts are an entire race of Eldritch Abominations, the ones with more animalistic forms fit this trope, such as the Powerwilds, Bouncywilds and Pot Spiders. But even among them, there are a few that stand out:
 * Skoll, a massive wolf Heartless named after the giant sun-chasing wolf from Norse Mythology. It fights by summoning packs of ghostly wolf minions, firing off powerful ice attacks, and trying to crush Sora and friends underneath a mass of darkness big enough to fill up the sky. But what makes it really special is the fact that it's the Heartless of Prince Hans himself, who's been completely corrupted by the darkness in his heart.
 * Scar similarly becomes consumed by hatred and rage - but unlike Hans, his inner darkness is so powerful that he manages to hold onto his original form after becoming a Heartless... a feat only shared by Ansem, Seeker of Darkness..
 * The Halloween Hack has the Desire Dog, which appears as a Zombie Dog in the overworld - but in-battle, the front half of its body consists of gooey tentacle-like pseudopods that it frequently uses to attack, and upon death it collapses into an array of wriggling tentacles.
 * Final Fantasy:
 * Final Fantasy VIII: During the third stage of the Final Boss, Ultimecia the Sorceress (a Sorceress effectively being an enhanced human) junctions herself unto the Guardian Force Griever, resulting in a hybrid felinid form with Ultimecia's torso and arms on its chest, and deformed limbs and wings resembling Ultimecia's.
 * Sin of Final Fantasy X manifests as a giant whale-like monster the size of an entire city, and emerges from the depths of the ocean to completely annihilate all settlements larger than small villages at random intervals. It leaves swarms of smaller monsters in its path and everyone who survives coming into contact with its toxins (fortunately) suffers from massive memory loss. And apparently, it can wipe out entire armies by causing distortions of space.
 * Deadly Premonition has one where you'd least expect it, personally confirmed by the creator:.
 * In Monster Hunter, Elder Dragons as a whole are essentially this by the standards of the local fauna. They're incredibly powerful monsters that don't fit into the tree of life like every other monster classification, and often have their powers manifest in ways that can't be explained away by an elemental sac or any biological function. Many are either worshipped and revered as gods, or else feared as demons, and their presence drives away other monsters through an environmental anomaly.
 * The Elder Dragon Yama Tsukami is weird even by this standard - it looks nothing like a traditional dragon and more like a gigantic floating octopus covered in moss and earth, possessing a mouth full of disturbingly human teeth. It isn't aggressive or malicious, but it can destroy entire ecosystems by devouring everything it flies over, including entire lakes and forests.
 * Fatalis and its relatives are easily some of the most eldritch and unholy monsters in the series, which is no small feat. Armor and weapons made from their body parts are said to plague those who wield them with horrifying nightmares, dark voices in their heads, and animalistic bloodlust; the Fatalis sword in Pokke village is constantly regenerating scales as well... These weapons and armor tend to driver their users insane if they don't die under mysterious circumstances - they can also possess their wielders, and possibly turn them into another Fatalis entirely. Between this and, this implies that it's impossible to truly kill a Fatalis since they'll always find some way to resurrect. Their powers are also anomalous even by the standards of other Elder Dragons: Crimson Fatalis can send meteors crashing down to Earth, while the White Fatalis is introduced triggering a solar eclipse by emerging from a mysterious portal, hinting that it might be extradimensional to some extent. The standard Black Fatalis is comparatively more mundane, but even it famously wiped out an entire civilization overnight.
 * The Legend of Zelda franchise has Ganon, who often appears as a large boar-headed demonic being, and sometimes even closer to an actual boar (though still monstrous and far from any less abominable).
 * The Legend of Zelda: Twilight Princess has the second stage of the Final Boss:.
 * In The Legend of Zelda: Breath of the Wild, during the Final Boss fight.
 * Super Smash Bros.:
 * Ganondorf turns into his demonic boar form as part of his Final Smash from Super Smash Bros. Brawl onward.
 * Super Smash Bros. for Nintendo 3DS / Wii U introduces the Master Core - either a superpowered form of Master Hand, or some sort of abomination that took his guise. It surrounds itself with The "Swarm", a mass of darkness that it can shape into a number of terrifying forms: the ones that qualify for this are the Master Beast, which appears as a scorpion-tailed hound with violent high-speed attacks and bites that can shake the stage, and the Master Shadow if you're using an animal-like fighter.
 * Falzar and Gregar from Mega Man Battle Network 6 overlap with Mechanical Abomination - both are obscenely powerful, animalistic superprograms that are feared as harbingers of the apocalypse, and serve as the game's version mascots. Gregar is a wolf-like amalgamation of bugfrags not unlike Gospel, and Falzar was meant to be a countermeasure that turned violent and unpredictable. When MegaMan.EXE is forced to absorb one, he turns into a feral and uncontrollable Mechanical Abomination due to their raw power, with his appearance altered accordingly.
 * The Pokémon series has an abundance of examples, typically in the form of its Olympus Mons.
 * The super-ancient trio of Pokémon Ruby and Sapphire - Groudon, Kyogre, and Rayquaza - are Weather Control Creatures that lurk in places normally beyond the reaches of man, and the awakening of either the dinosaur-like Groudon or the whale-like Kyogre alone constitutes an apocalyptic event that could devastate the world. The third version, Pokémon Emerald, has both of them awakened, forcing you to find Rayquaza in order to force them back into slumber. All three of them are at least Phsyical Gods with an ability to control the continents, ocean and sky, respectively, and they're all believed to be hundreds of millions of years old. Where Groudon and Kyogre can also induce droughts and flooding, Rayquaza can outright force clear skies with its presence. Pokemon
 * The fact that you can catch such world-changing entities to begin with is worthy of noting - Poké Balls work as power limiters that allow you to control what you catch with them. As pointed out by Ghetsis in Pokémon Black and White: "A Pokémon, even if it's revered as a deity, is still just a Pokémon" - this also factors in the plot of Cyrus, who wants to control the masters of time and/or space in Pokemon Diamond/Pearl/Platinum by using the Red Chain rather than any type of Poké Balls.

Visual Novels

 * In the Nasuverse, Tsukihime has Nero Chaos, whose body is composed of hundreds of animals that can detach from him to attack and feed.

Web Original

 * SCP Foundation:
 * A prime example is SCP-682 ("Hard-to-Kill Reptile"). A reptillian being of indeterminate gender, it's not only extremely intelligent and capable of speech, but also ridiculously adaptive, extremely destructive and tough to bring down - and the Foundation wants it destroyed as soon as possible. It has regeneration abilities that allows it to survive several factors of otherwise-lethal force - extensive testing reveals that anything that even manages to do significant damage only "works" once. What makes it abominable is that, as indicated by its own words, it finds human life "disgusting" and tries its damnedest to kill anyone and everyone it can get within reach of - the SCP thought to be God by the Foundation claims it's "not one of his", and it is such a biological mystery that researchers wonder if it's even "alive" insofar as we understand the concept.
 * ...And as shown by that testing and its character page, the questions don't end there. It's well-established that said testing is extremely unlikely to result in a successful kill - beyond gauging its durability, these tests would ideally reveal more about the creature's properties and origins.
 * SCP-5683 is an arachnid-like being that adapts its form to resist anything posing a danger to it. It doesn't seem to be particularly intelligent, but is smarter than it looks and still a capable hunter, especially with its ridiculously adaptive body - it's extremely destructive and tough to bring down, and the Foundation wants it neutralized as soon as possible. It absolutely hates humanity and tries its damnedest to kill anyone and everyone it can get within reach of - sound familiar? One of the staff assigned to it even dealt with SCP-682 previously, and seems quite ambitious about handling this one.