The Abominations were implanted with amplifiers and administered chemical agents to aid in the development of psychic abilities, while undergoing telesthetic amplification sessions to become Replica Commanders. However, the invasive process of improving and attuning the subjects' psychic fortitude caused extensive neural damage to the candidates, causing them to regress into a violent animalistic state. Symptoms of early psychological decay within the testing studies were incessant paranoia, hallucinations, nightmares, and loss of logical thought.
Although the developmental stages caused the Abominations to become extremely dangerous and unsuitable for being rational commanders, they were successful in obtaining the psychic capability to fully control Replica Soldiers while in an Amplifier machine, but that ability was useless in its entirety due to the failed subjects possessing inadequate mental control of their own selves and of the replicated soldiers.
Abominations prove to be dangerous to themselves, as they are sometimes seen with bandages wrapped around their heads, and always have severe wounds and rashes. They are kept in a "holding area" in the Paragon Facility, a prison-like area with several rows of tiny, crude metal cells, equipped with mattresses. Michael Becket is attacked by several throughout the course of F.E.A.R. 2: Project Origin. At several points in the game, they can be seen attacking enemies and brutally slaughtering them, severing their heads and spraying blood. They attack anything in sight, and have no allies.
These monsters are only fought in four levels: Discovery, Withdrawal, Replica and Snake Fist. Most of the time, the player will fight a group of them, except in the level Withdrawal, where only one is fought.
Prior to the player's first encounter with the Replicas, an Abomination can be seen sitting in a Psychic Amplifier as images flash in front of it on the screens. The Abomination is struggling and roaring, either mad with pain or attempting to get loose. After killing an enemy, they often scribble images on the walls or on the floor using their victims blood, along with the words: "Can he see?".
Foxtrot 813 encounters several abominations in F.E.A.R. 2: Reborn. At the last section, where the player fights them in the big circle chamber, if they aren't all dispatched before the Remnant spawn is triggered (which is triggered once the player gets to the bottom of the pit), the player will have to fight both enemies at once. Interestingly, despite belonging to technically different forces, they will not attack each other.
Abominations are savage, humanoid cannibals. They often wear hospital pants, but are sometimes naked. When they are not wearing pants, it can be observed that they do not have genitals; this is either for censorship, or they were surgically removed for unknown reasons. Their faces are mutilated; this appears to be self mutilation.
The extent of how the project's research affected the Abominations negatively can be observed from their grotesque physical appearance. Some Abominations can be seen to have stitched skulls, where the likely procedure of neural implant surgery was performed on their brains. Several white circular markings are located along the bodies of the test subjects, where diode devices to assist in psychic activity are to be located internally, and are able to be easily connected to other supportive systems, such as a T.A.C. chair. The Abominations are the frightening aftermath of inhumane attempts to excel a human's brain and body to supernatural lengths, ultimately destroying the sanity of the individual in return for power.
Abominations are lethally quick and have the ability to run on walls, coupled with quick hit-and-run melee attacks that deal a lot of damage. Thus, they share very similar abilities as Replica Assassins. Unlike the Assassins however, they cannot turn invisible and they can grab hold of Becket. In the latter scenario, only repeated meleeing will shake them off. The sounds they make are animal-like and will alert the player to their presence.
- The player should listen for the animal-like sounds they make as a warning. Hitting Slow-Mo once their sound is heard will make the player better able to avoid a heavy hit.
- Abominations can pop out of everywhere, including the ground and ceilings, amongst other places. They also have the ability to crawl on ceilings and the sides of walls/glass windows.
- They mostly like to attack when the player isn't looking, especially from behind.
- It should be kept in mind, where there's one, there's almost always another two or three or four.
- Abominations typically run away when faced, so they can hide again and surprise the player.
- The SHO Series-3 Combat Shotgun and Andra FD-99 Submachine Gun are arguably the best weapons for anti-Abomination work: the former because they have to get close to hit the player, the latter because it fills the air with lead and is more common than AR ammo early in the game.
- Slow-Mo should be used as much as possible. Abominations are fast, and they like to hit and run.
- The player should try to get into a sheltered or secluded area (e.g. a prison cell) to force the Abominations to come through a small doorway in order to reach them. This gives them a predictable point of entry. The player should wait patiently with their back against a corner with their shotgun out. If motion is seen, use Slow-Mo and fire.
- They die with one point blank shot from any shotgun, which means they have less health than most Replica Forces.
- If Becket gets jumped by one, the only thing the player can do is spam the melee button.
- After they are meleed off, a good way to kill them is to slidekick them while they are on the ground, which on easy always results in an instant kill.
- The player should not run from Abominations due to their speed.
- The symptoms of insanity observed in Abominations match those of Alma Wade, who also suffered severe mental side effects due to her telepathic powers.