Genocyber

An ultraviolent OVA from 1993 about two psychic sisters - one mute, one crippled - who can merge to form a mutant creature called the Genocyber. There is also a manga that only got through some of the first episode's plot; reading it first reduces the Mind Screw levels a fair bit.

Genocyber was directed by Koichi Ohata, who also directed MD Geist, Cybernetics Guardian and Burst Angel.

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Genocyber contains examples of these tropes:

 * Adaptation Distillation - One could make a case that the anime's changes were for the better. For example, the Faceless Goons being mute makes them High Octane Nightmare Fuel as opposed to being simply a tad disturbing, and the infamous "shredded children" scene is totally absent from the manga.
 * Barbie Doll Anatomy
 * Blind Seer - Mel, from the fourth and fifth episodes, tries to obtain money by fortune telling with her amazing psychic powers.
 * Body Horror
 * Cluster F-Bomb - the dub of the first 3 episodes. Due to the dark, gritty Cyberpunk atmosphere they create, it works extremely well, and dropping it for the last two was a mistake in this troper's opinion.
 * Cute Mute - Elaine is mute, although she does occasionally communicate using her Psychic Powers and body language. In the manga neither sister was mute.
 * Cyberpunk - Interestingly enough, this is one of the few anime that actually sticks to the Cyberpunk mold. Most so-called cyberpunk anime is actually Post Cyber Punk.
 * Dystopia
 * Eye Scream - One of various examples of the Gorn in the manga. In fact, it actually happens twice- once to a random Red Shirt in the first chapter, and once to Diana in the third chapter. It also happens a few times in the anime, most noticeably in the first episode where the title mecha uses one cyborg mook's eye sockets as a hand-hold to tear its spine out.
 * Faceless Mecha Mooks - Faceless and mecha, yes, but the mook part is played with. In the manga, they're very talkative and other than one beating the living crap out of Diana, their badassery is something of an Informed Ability. However, in the anime, we're given a close-up view of the handiwork of about 20: a hospital hallway absolutely covered in horribly mutilated corpses and body parts, followed by them horribly torturing the only witness. The most recognizable corpse is a nurse, whose head slowly detaches itself and falls off to the right, tendons visibly and audibly just snapping as it does so.
 * For the Evulz - The Faceless Goons slaughter a bunch of hospital workers and mutilate a detective for no apparent reason in the first episode. There's also the whole, you know, torturing two innocent girls to make them go nuts and form a large green demon-robot-thing for no reason bit.
 * Gorn - The OVA contains such delightful sights as the aforementioned hospital scene and a scene of children being shredded by helicopter miniguns; the former is legitimately High Octane Nightmare Fuel, whereas the latter could be considered Narm.
 * Harmful to Minors - The entire manga is essentially Elaine and Diana getting tortured.
 * High-Pressure Blood - Surprisingly, only one usage is noticed. In the first episode, a mook is given visions of bugs crawling in his head by an unconscious Elaine, which prompts him to tear open his scalp, causing blood to spray all over the surroundings. The rest of the gore is rather realistic, especially in the second episode; the gunshot wounds aside from a head-explosion are disturbingly life-like, and they actually took care to draw the tibia and fibula snapping along with the muscle tearing on an ankle shot. However, said head explosion catapults the scene into pure Narm territory.
 * How We Got Here - The first chapter of the manga is set at the end of the story.
 * Humongous Mecha
 * Infant Immortality - Averted multiple times.
 * In the first episode, Elaine's friend gets murdered as an incentive for her to come back and form the Genocyber.
 * The second episode begins with children being disintegrated by a helicopter minigun.
 * Mad Scientist - An unnamed one is responsible for the creation of the Genocyber.
 * Mind Screw - There is almost no exposition whatsoever aside from a Mad Scientist explaining how the Psychic Powers work in the beginning of the first episode. This makes the totally unexplained Time Skip between the first two episodes even more bizarre.
 * Painful Transformation - The creation of the Genocyber, supposedly. We see it from within her psyche, and get glimpses of  afterwards, while her screams for   play in the background.
 * Pink Mist - A child is shot in the head with a helicopter minigun in the series' absolute most infamous scene. It essentially vaporizes everything above his upper lip.
 * Person of Mass Destruction - Once the two sisters come together to form Genocyber, nothing is left standing!
 * Psychic Powers - Called "Vajra", but the idea is the same. It's more akin to the "vectors" from Elfen Lied, in function if not in form.
 * Shout-Out - A very weird one. The first episode, in both languages, starts with a scientist asking "What's the frequency, Kenneth?".
 * Super Soldier
 * The Future - The third story--which comprises the fourth and fifth episodes--is set in the year 2400.
 * Time Skip - The time between the first and second arcs is unspecified, but the time between the second and third arc is about 400 years.
 * Transformation Trauma - The OVA practically runs on this and Gorn.
 * Woobie, Destroyer of Worlds - Elaine.
 * Woobie, Destroyer of Worlds - Elaine.