In most cases, the traditional Eldritch Abomination is something completely outside human comprehension. Maybe they're incredibly ancient, maybe they came from another dimension, or maybe they don't even obey our laws of physics. But sometimes, they have much closer ties to humanity... because humans made them. Enter the Genetic Abomination.
This is a specific subset of the classic Eldritch Abomination that is not a naturally-existing being, but was created and cultivated artificially, usually through genetic engineering. That doesn't make them any less horrifying — and in some cases, it could make them more so, since they are so different from the natural organisms used in their creation and proves how powerful their creator's capabilities really are. Their resemblance to natural organisms varies. At best, they'll just look like a warped version of the creatures that they were derived from, putting them in Animalistic Abomination territory. Other times, though, they'll bear absolutely no resemblance whatsoever to anything that ever evolved naturally.
The reasons for the creation of such a being are variable. Often it's some sort of living weapon that the creator would proclaim as their Magnum Opus, but it's also common for them to be created for other purposes. Note that to qualify for this trope, a creature cannot merely be a large, terrifying genetically engineered beast— it must also fit into the established definition of an Eldritch Abomination. This entails being inconceivably horrific for the majority of minds that encounter it, but (in a step-down from a natural abomination) not inconceivable to the mortal mind in general; after all, it was a certain kind of mortal thinking that brought it into existence.
A Sub-Trope of Genetic Engineering Is the New Nuke, seeing as it was bio-engineering that created these horrors. Likely to overlap with Bioweapon Beast if they were created for combat purposes, and can be a Custom-Built Host for a real Eldritch Abomination. Might have Escaped from the Lab. For other artificially created Abominations, see Mechanical Abomination, and if both tropes overlap, the combination results in an unholy example of Organic Technology and Meat-Sack Robot.
- Battle Angel Alita: In the Last Order books, we are introduced to the Republique Venus. The people of Venus have mastered bio-engineering, and make use of it in every facet of their society. As a result, a lot of Venusian people and objects are living creatures, as demonstrated in here, where we see Zekka's DNA has been used to make things from food, to pets, to furniture.
- In Bio-Meat: Nectar, Bio-Meat are genetically engineered creatures designed to be able to eat anything as well as serve as an ample food source. The creatures themselves are shaped like dog-sized leeches with lamprey-like mouths that open down to their bellies and spindly arthropod legs. When an earthquake frees them from containment, they immediately go on a rampage and start devouring any and all organic material, plants, animals, and people alike, leaving absolutely nothing left in their wake.
- Digimon Adventure gives us Kimeramon. Despite being a digital lifeform and not being "real" in a traditional sense, it's a monstrous kitbash of several different Digimon that have been synthesized together.
- Dragon Ball: Cell, a bio-engineered life-form created by Dr. Gero from the DNA of the strongest fighters in the setting, including Goku, Vegeta, Piccolo, and Frieza. He's capable of using all of their signature attacks as well as possessing all of their most advantageous natural traits (the Saiyans' ability to grow stronger through combat, Namekian regeneration, and Frieza's ability to survive in almost any environment and any fatal injuries, including self-destruction). Cell also possesses a long tail with a syringe-like apparatus that he uses to inject victims with enzymes and literally drink them whole to gain even more power, doing so to hundreds of thousands of humans. He runs rampant for days terrorizing humanity before being defeated by Super Saiyan 2 Gohan.
- Humanity was originally created by the Uranus as a race of soldiers, with an adaptable and intelligent base form that could then be artificially metamorphosed into one of various types of Zoanoid — Bioweapon Beasts with specialised abilities ranging from brute strength to organic laser cannons. Each human was implanted with a genetic Restraining Bolt which would force them to obey the telepathic commands of both the Zoalord commander units and their Uranus masters. But when they tried bonding a human with the bio-boost organism that served as their standard-issue spacesuit, wanting to see what would happen if it "maximised the host's ability to survive", things Went Horribly Right. Not only did the bonding process transform humans into Persons Of Mass Destruction with the combined powers of many Zoanoids, it also made them Immune to Mind Control. They named the resulting creature "Guyver", meaning "out of control", and became so spooked by how easy it was to create one that they abandoned Earth entirely (and even attempted to destroy it out of fear that an army of Guyvers would one day come after them).
- In the modern day, the "Lost Numbers" are byproducts of Nebulous Evil Organisation Chronos's experiments in creating new varieties of Zoanoid, whose DNA became unstable after being augmented too many times. This grants them strange and unique powers, but also disables their Uranian control genes, meaning that anyone unlucky enough to achieve this status ends up relegated to a suicide squad. And then there's Aptom. Formerly a shapeshifting Lost Number, he somehow mutated into an entirely new form of life — the cells of his body transforming into a Hive Mind of Thing-like parasites that can take over the bodies of other Zoanoids and mimic their forms. When Aptom needs to fight, he transforms into a Shapeshifter Mashup form combining the best aspects of multiple Hyper Zoanoids in a single body. Eventually Aptom switches sides and joins the Guyver protagonists... and in an Ironic Echo of their former masters, Chronos covers up the truth of his creation by claiming that he's a Guyver (which by the original definition, he is).
- Hunter × Hunter: While not born in a lab, Chimera Ants are made from the DNA of whatever the Queen eats, resulting in hideous amalgamations of animals. Ants made from humans gain their intelligence and the ability to use Nen. The Royal Guards and the Chimera Ant King have the biggest, most eldritch auras capable of driving other Nen users to madness if they get close enough, as was the case with Knov who was not only driven to near-insanity, but ended up losing all his hair from the stress the Royal Guards' aura put on him.
- The God Warrior from Nausicaä of the Valley of the Wind is explained in the manga to have been a genetically engineered superweapon, but when we see it it's a horrifying monstrosity with only the vaguest resemblance to any sort of living creature.
- Sailor Moon: The Daimons during the Infinity Arc, though the 90's anime and manga present distinct varieties. In both versions, they're the resulting hybrid of Professor Tomoe's experiments using alien technology he'd received from Pharaoh 90. In the anime, the Daimons are merely the season's Monster of the Week resulting from a cultivated egg implanted into a mundane item. In the manga, they're more overtly lovecraftian monsters with the egg planted inside people. In both versions, Tomoe's research lets him become this himself himself during his fight with the Sailor Guardians, though since he was merely possessed in the anime, he also gets to live afterwards.
- Ultimate Spider-Man:
- The Venom symbiote is a cure for cancer turned experimental bioweapon. It can shapeshift to point that it’s practically a Blob Monster at times and actively eats its host unless it consumes a constant amount of flesh.
- The Carnage symbiote is the result of Dr. Curt Connors mixing a sample of Spider-Man's blood (which contained trace amounts of the Venom symbiote) with his own (which contained the Lizard serum) and a leftover sample of Richard Parker's Venom Project. The result is a blood-red monstrosity that needs to drain other living creatues of their blood and body fluids to sustain itself.
- Watchmen: The giant psychic squid, which is teleported into New York City and kills millions with its telepathic death throes. It was genetically engineered by Ozymandias to be a "fake" Eldritch Horror, to unify all of humanity against the perceived common threat of psychic squid aliens.
- We Kill Monsters: All the monstrosities that have been attacking Kern County are animals genetically modified by Tronco's pharmaceutical subsidiaries to produce large amounts of a certain kind of DNA they intend to put in all the products of the companies Tronco owns for humans to consume.
- Alien: The Xenomorphs are hive-minded monsters with both endoskeletons and biomechanical exoskeletons, extremely corrosive blood, and two sets of jaws; which reproduce by infecting hosts and integrate biological traits of their host species into themselves, with a wide degree of phenotypical variation on top of that. The prequel films and novels reveal they were created using a mutagenic black ooze with the intent of exterminating entire planets, and that the secret behind their reproduction involves a virus — a modified form of said black ooze — that infects the host, causing them to develop a tumor that metastasizes into the Xenomorph larva.
- Biollante from Godzilla vs. Biollante is this crossed with Botanical Abomination, being a genetic chimaera of rose, human, and Godzilla DNA that mutated from a towering plant with a toothy rose flower into a titanic, bizarre dino-plant hybrid. She's not actually malevolent, however, and is outright kind and docile towards humans due to having a human soul.
- The Kaiju of the Pacific Rim series are manufactured giant monstrosities created for the purpose of wiping out humanity so their creators can move in. Their appearances include more than two arms, giant blade-shaped horns on their heads, Nested Mouths, and in one case, the eyes were located UNDER the mouth on their head.
- All Tomorrows: In the distant future, humanity goes to war against the Qu, a race of Scary Dogmatic Aliens... and they lose. The Qu punished the survivors by turning them into these. Many of these creations would qualify as Woobie Species, such as the Mantelopes, who were changed into grazing ungulates but retained their human intelligence and sapience — they cannot talk or do anything in their new bodies but vividly recall their past forms, so they spend their centuries wandering the plains of their world, screaming and singing in despair. The worst of all are the Colonials, who have been reduced to sewage-filtering bricks of flesh that reproduce like cancer cells...with their sentience left fully intact.
- Dune: The Bene Tleilax are a reclusive, xenophobic religious group that sell their genetic creations to the highest bidder. Both their actions and their products (mostly the latter) have made them reviled by the overwhelming majority of humankind. And yet they still prosper because of how useful their inventions are in the constant power games and intrigues of the Landsraad. Most notably their Face Dancers and Axlotl Tanks.
- Frankenstein: Quite possibly the Trope Codifier; a very large portion of genetic abominations have been influenced by the classic creature himself- Frankenstein's monster. Though his intentions and personality are completely different (he does have an intelligent human mind), his basic concept is still incredibly important. It should be noted, though, that the monster is itself not a Genetic Abomination for the simple reason that the novel predates the idea of Mendelian genetics, never mind genetic engineering.
- Horus Heresy: The positively nightmarish creations of the self-described "Worker of Obscenity" Basilio Fo, from the novel Misbegotten. None of them look remotely human and yet it's obvious they were made from humans.
- Nemesis Saga: The Aeros specialize in creating colossal Bioweapon Beasts called Gestorumque, some of which are capable of sensing emotions and moral guilt, and use them to facilitate their conquest of the multiverse.
- Power Rangers Time Force has these as the main antagonists. Ransick in particular was spawned from a genetic engineering accident in the 31st century, and his treatment at the hands of humans made him resentful of non-mutants, leading him to form a dangerous gang of mutant criminals.
- Red Dwarf has several of these:
- The Despair Squid, an apex predator resulting from an artificially enhanced evolutionary arms race. "It's got three alternatives — it thinks we're either a threat, food or mate. It's either gonna kill us, eat us or hump us."
- The Polymorph, a genetically-engineered shapechanging emotional vampire.
- The Gelfs, Genetically Engineered Life Forms who are... basically just ugly.
- Emohawks — semi-domesticated Polymorphs used by the Gelfs to trade emotions, and also to get back at people who cross them.
- GURPS: In keeping with the game's assumption of a realistic baseline, most of the products of imagined future biotechnology in supplements such as GURPS Bio-Tech are relatively low-key, but a few are abominable, such as the scary "Chronos" (genetically engineered warriors) or the venomous neo-vampire bat.
- The Gene Pools in Splicers. They start out as tentacled Starfish/Octopus things that are implanted in the abdomen of a volunteer to mature. This person is called a Saint, who serves the Resistance as a healer. When the Gene-Pool matures fifty to seventy years later, it leaves the Saint(killing them, a price the Saint knew about when they signed up), creates a pit in the ground, and merges with yet another volunteer, who will be known as an Engineer. This time the Pool extends its tentacles up the volunteer's legs, and comes out the back like a grotesque set of alien wings. This roots the Engineer to one spot for the rest of their lives, the machinery by which the Resistance creates their Host Armors, Gore Hounds, War Mounts, and other bio-weapons. Some Gene-Pools are mutants known as Brain Pools. When a Brain pool matures, it flips over, turning into a huge slime-covered mound of Brain-flesh. The tentacles of this creature don't merely merge with a volunteer, they rip them apart, leaving a horrific collection of limbs and organs (and the volunteer's head) attached to the tentacles. This is a Librarian, who acts as a living computer who stores information and develops new Biotechnologies. they are literally the brains of the resistance, but occasionally suffer bouts of megalomania.
- Warhammer Fantasy: The Skaven, especially Clan Moulder, uses many rat-like abomination like Rat Ogres into their roster, but their Hell Pit Abomination takes the cake. It's an amalgamation of warpstones, cogs, pale skills, dragons, and still-living Skavens, stitched together and constantly rousing in pain. Though rarely seen, it is extremely destructive.
- Colossal Kaiju Combat!: The Progenitor version of C'thura is an eldritch Bioweapon Beast created by extra-dimensional entities to spread terror and destruction so that they can conquer Earth unimpeded.
- Daikaiju Daikessen Versus: Ascha'Vovina and its siblings are Draconic Abominations engineered as Bioweapon Beasts by an evil god.
- Dark Escape 4D has giant insect monsters with human upper bodies on their backs, quadropedal creatures with a mouth that extends out from their "heads", and the bosses are something else.
- Dragon Ball Fighter Z: Android 21 is an even bigger amalgamation of several powerful beings and scientists, including Cell himself. This gives her the potential to be far more powerful than Cell could ever be, access to an even bigger arsenal of tricks, and high intellect to match. However, due to her being partially made from cells originating from Majin Buu, Android 21 is in a near-constant state of hunger that she tries so hard to suppress. This makes her a threat not only to Earth, but the entire universe unless she is stopped in some way.
- The Fallout series has a wide variety of mutated eldritch horrors. There's Centaur, Floaters, Fog Crawlers, Mirelurks, and the unforgettable Master?
- Fallout 3’s Mothership Zeta expansion features a genetically engineered enemy literally called “Abomination” that is the unholy fusion of humans and the Zetan aliens that the DLC revolves around.
- Horizon Forbidden West has this as the final fate of Theodor "Ted" Faro. Courtesy of a botched longevity treatment, by one thousand years after the end of the world, he is a gigantic tumor several stories tall. Even those who would have worshiped him recoil in disgust and Mercy Kill him. With centuries of immobile isolation, he can only howl at people, not even talk. The player doesn't get a good look at him, but judging from the reactions of Aloy and the Ceo, they wouldn't want to.
- The Metroids are creatures artificially bioengineered by the Chozo to devour the X-Parasites on SR-388, only to turn out to be so ravenous that they started draining the Life Energy of everything else on the planet, including their creators. They can metamorphose into different forms depending on their environment, as well.
- Experiment No. Z-57 from Metroid Dread. The "abomination" part comes from the fact that it looks like a horrifically mutated lizard with a Flower Mouth, spider-like tentacle-limbs and a slug-like tail, can breath lasers that leave some sort of goop behind, and clogged the heat generator with said goop despite being much smaller than said generator. The "genetic" part comes from the fact that it was created by the Mawkin, with it being made from the DNA of multiple creatures, most obviously a Corpius. This fact is enforced by it not even having an actual name, with it simply being called "Experiment No. Z-57".
- Pokémon Red and Blue's strongest Legendary Pokémon, Mewtwo, was created by scientists after years of horrific genetic experimentation.
- [PROTOTYPE]: The Redlight and Blacklight viruses were engineered as bioweapons and bestow nightmarish abilities on compatible hosts, but mutate anyone who isn't a compatible host into ravenous zombies or predatory monsters connected to a hive-mind. In the second game, a Gentek scientist even lampshades how little about the mutagen makes scientific sense, only to be told to shut up and not think so deeply about it.
- According to the backstory, the Bydo from R-Type is a fleshy bioweapon which is created by humans and it's made of modified human DNA. Its performance is a huge success, until the Bydo goes out of control, infecting and corrupting both living and mechanical beings into enemies the player spaceship fights.
- The third stage of Shinobi III: Return of the Ninja Master, after dodging deadly acid pools and fighting hordes of hopping brains, Joe finds a giant mass of Meat Moss and a humanoid thing in the sewers beneath the bio-lab. This serves as the boss of the level.
- Shrak For Quake is full of these. In fact, it's the entire premise of the game.
- Starcraft II has the Hybrids, created by mixing DNA from the Protoss and the Zerg in order to serve as servants of and vessels for the rogue Xel'naga, Amon. The Protoss and Zerg themselves are both products of earlier rounds of Xel'naga engineering, and the Zerg qualify for this trope themselves.
- Star Fox 64 has Vulcain, Andross's nightmarish bio-weapon on Solar. Seeing it causes Peppy and Falco (if they're present) to vocally register disbelief at how mad Andross actually is for making something like that:
Peppy: This is the enemy's bio-weapon?!?Falco: Andross is an insane fool!
- In Undertale, the Pacifist epilogue starts by the exploration of the True Lab, a place where Alphys (and possibly Gaster before her) experimented on Determination on monsters, and where the only results are horrible fusions of the Ugly Cute creatures of the Underground. This includes some weird spoon monster which waits for your character to go into a bed before... covering them and petting their head, another one hiding behind the curtain of a bathtub which disappears right when you open it, and among the ones you fight, the Endogeny may be the most confusing one, as it is a fusion of five different dogs (which are represented in the negative spaces between its six legs), it shakes uncontrollably as the battle progresses, and when it's appeased, the negative spaces suddenly have happy faces. One of the lab entries mentions an injection of Determination in a flower taken from Asgore's garden... and another one that it escaped.
- Sluggy Freelance: During a battle between supervillains, a minion of the Nofun Corporation, which specializes in viral mutagens, tosses a vial of "Cheesy Bossmonster Virus" in the direction of Dr. Shankraft's minions, and one particularly stupid one mistakes it for a jello shot and drinks it. This causes him to grow an eyeball in his chest before mutating into a colossal tentacled monster with More Teeth than the Osmond Family.
- In the Rick and Morty episode "Rick Potion No. 9", when the Love Potion Rick made for Morty becomes contagious, Rick makes an antidote out of mantis DNA that just mutates everyone into giant mantis monsters. The antidote he makes for THAT is a combination of several different animals that turns everyone on the planet (minus Morty's family) into a wide variety of horrifying genetic monstrosities that Rick calls "Cronenbergs".
- Scooby-Doo! Mystery Incorporated: The Skull Cattle, bovine-like super predators created by Professor Pericles from the DNA of cows, bees, and piranhas that can survive in almost any environment and devour everything in their path. When the gang release them into the ocean without thinking of the consequences, they all decide to just look the other way.
- Spliced: The premise of the series is an island populated by mutant organisms created from various organic and inorganic objects by a doctor who was eventually arrested. Just how much of this trope varies depending on the character, from Adorable Abomination-level ones like Fuzzy Snuggums to more eldritch-looking ones like the radioactive dinosaur-spider.
- In the Squidbillies episode "Wing Nut", Dan Halen used genetic engineering to try and create the perfect chicken to serve in his restaurant "Ain't Nothin But A Wing" by combining chicken DNA and squid DNA. The ultimate end result was a featherless horrifying monstrosity with a body covered in chicken legs and no beak that was then modified to exude ranch dressing onto itself. Eating them causes the customer to grow tumors and explode.
- In Star Trek: Lower Decks Tendi creates The Dog, a Shapeshifting Labrador Retriever. Being an alien, she had no idea what an Earth dog could actually do, so she ended up giving The Dog a bunch of freaky powers by mistake.
- Though its occurence is almost never artificial, cancer counts. The name itself strikes fear into those who are diagnosed with it, and though many studies have been done to understand it, many still die of it every year.
A Genetic Abomination borne of mutations, its physical form is similarly aberrant; malformed tumors and patchwork vessels, unholy fusion of both healthy and rogue cells. It will continue to grow, eventually spreading its invasive tendrils to other organs, choking and killing them, and thus their host. It is invasive yet evasive, preventing the immune cells from killing it, and able to spread to other loci, seeding new masses of malformed flesh From a Single Cell. Some tumors are even able to differentiate their cells just enough to grow organs like hair and teeth in random spots, making them particularly grotesque. The fact that its diagnosis often justifies Harmful Healing is testament to its dreaded status; treatments that will cause severe damage to healthy cells is considered an acceptable trade-off in the attempt to kill this abomination off, and sometimes even that's not enough.