So, you've got a Super Soldier program, perhaps an AI research initiative, an organization that has access to all sorts of Phlebotinum goodness for its operatives, or some other cutting edge experiment designed to alter or Create Life.
Maybe the streams crossed, the Super Serum is actually of the Psycho or Toxic flavors, the janitor tossed rotten tomatoes at it, the psych evaluations weren't as rigorous as they should have been, or an honest to goodness unforeseen complication happened during Alpha Testing (if there was any, that is). Whatever the case, the experiment has Gone Horribly Wrong and the first and eldest of a nascent Chosen Many has gone rogue (and not in the good way), is evil, and likely wants to kill its makers and younger siblings.
Or, more chillingly, it is the result of an experiment that has Gone Horribly Right.
This tends to happen very frequently to projects started by altogether good conspiracies who want to create an army of heroes. By the time they get around to perfecting the process and the hero undergoes it, "big brother" will show up and either "offer" to form a Secret Project Refugee Family after killing their "parents"... or kill him dead if he refuses. Or if he agrees. Inevitably, any previous version of a hero who reappears is invariably evil.
Expect this monster to be named some variation of Alpha, Proto, or Zero.
- In the Zone of the Enders Prequel Idolo, the Metatron used to power the Orbital Frame is a slow acting, sentient Psycho Serum. It turns the pilot, Radium Levans, into a hateful and destructive force, while enabling him to use Idolo's powers to their destructive apex.
- Hidan from Naruto; his inability to die resulted from a religious experiment. Only problem is, the god of said religion praises the slaughter of one's neighbors, which didn't bode well for Hidan's village (or anyone else for that matter).
- Some incarnations of Atlas from Astro Boy.
- The Mad Pierrot from Cowboy Bebop.
- The Prototype and Test Type models 00 and 01 of Neon Genesis Evangelion. 01 is a bloodthirsty Mama Bear when it comes to her pilot, and 00 actively attempted (and failed) to kill hers.
- The ZERO System from Gundam Wing may qualify. A combat system created for the Super Prototype Wing Zero, it feeds an incredible amount of battle data and suggested courses of action directly into the pilot's brain. The problem being that using it requires exceptional mental focus: if your mind drifts even a little, it causes a slippery slope chain reaction that leads to the pilot being driven insane (either temporarily or permanently based off their mental fortitude). Throughout the series, all the main characters use it but only The Hero and The Rival are considered to have "mastered" it (though The Heart comes close).
- The Extended of Gundam Seed Destiny were pretty crazy, but when compared to their predecessors, the pre-Extended or biological CPUs, they're pillars of mental stability. The Extended can fake being normal. The pre-Extended were too Axe Crazy to so much as cooperate with one another, let alone be entrusted with spy missions.
- Captain America originally inverted this trope, with a number of his villains created by attempts to duplicate his Super Soldier Serum. Eventually, Protocide was introduced via Retcon, thereby playing this trope straight.
- Obviously, Norman Osborn, Spider-Man foe.
- Pretty much everyone in the Weapon Plus programme except Wolverine and Captain America qualifies. Almost without fail they were super-villains, and each was the first, and often only, in their generation of the programme.
- Valentine Romanov, eldest brother of Nikolai Dante, was the first Romanov to be bonded with a weapons crest. Unfortunately, his was a prototype which caused massive scarring, making him resemble a metallic skeleton along with some major Sanity Slippage.
- While Ash the android didn't technically go insane in Alien, it did engage in homicidal behavior, unlike the more "stable" later version represented by Bishop in Aliens. Also, Ash "malfunctioning" is merely the official explanation to cover up that he was fulfilling his mission to get the Xenomorph back to Earth without the interference of the crew.
- It turns out that Johann Schmidt/Red Skull in Captain America: The First Avenger was this compared to Captain America, receiving the same serum. It gave him more power, but it is implied to have also driven him insane and deformed him as a result.
- Albert Wesker from the Resident Evil films is implied to be this to Alice. Like Alice, he is injected with the T-Virus, and it is strongly implied that Wesker was injected long before Alice was. Likewise, after surviving a huge explosion, he regularly commits cannibalism in order to keep an imbalance of the T-Virus at bay as a result of the stress of surviving the explosion.
- This is the case with Mercutio in Idlewild by Nick Sagan. While he's not the alpha himself, the prototype's bitterness and jealousy bled into him and he goes insane. Eventually he kills several of his supposed friends as his grip on reality (such as it is in this Mind Screw of a book) slackens.
- In the third book in the series, "Everfree", one of the thawed-out Gedaechtnis employees admits to tampering with Mercutio's DNA to make him more dominant, because he was the only pure white subject.
- In Tad Williams' Otherland series, Mr. Sellars' backstory involves a secret military program to develop Powered Armor - one of the soldiers being trained for the program was mentally unstable and went on a psychotic rampage in a prototype suit, destroying billions of dollars of equipment and killing nearly all of his fellow personnel. Sellars himself barely survived, with horribly disfiguring injuries. The project was supposedly scrapped as a result of this incident, though Sellars notes that modern combat gear incorporates similar technology, albeit in a less One-Man Army form.
- A textbook example of this trope occurs in the Dean Koontz novel Mr. Murder, even having the superhuman clone assassin named Alpha. It is explained that their attempts to make him asexual just resulted in him being extremely sexually frustrated, as well as homicidal.
- The Faction Paradox novel Of the City of the Saved features Antipathy, the Ax Crazy firstborn son of the humanoid TARDIS Compassion. A psychotic TARDIS is a scary, scary thing.
- Sara Corvus, the self-proclaimed "first" bionic woman in the recent Bionic Woman series.
- Sylar/Gabriel Grey in Heroes started out as this. He was Patient Zero to Dr. Chandra Suresh, and it's partly due to Gabriel's desire to prove to him that he was special that drove him to start killing people and taking their powers. However, later RetCons have shown or implied that his Ax Craziness is also due to a couple other factors including his ability, his biological father, and some pretty serious childhood trauma among other things. So the guy didn't exactly have the stablest psyche before encountering Dr. Chandra Suresh.
- Lore (prototype for Data) in ST:TNG.
- Arguably, KARR (prototype for KITT) from Knight Rider.
- Knight Rider sequels follow the KARR formula. In Team Knight Rider the TKR AI car prototype KRO went crazy because his driver was crazy. In Knight Rider 2008 the second KITT had to face his own KARR predecessor which can transform to a robot. KARR (Knight Automated Roving Robot), KRO (Knight Reformulation One) and KARR 2008 (Knight Auto-Cybernetic Roving Robotic-Exoskeleton) are all prototypes that went rogue.
- Number One, "Cavil" from Battlestar Galactica Reimagined.
- On The Young Ones, landlord Mr. Bulowski becomes the accidental Psycho Prototype when he drinks Vyvyan's experimental potion and becomes an ax-wielding homicidal maniac. Subverted and lampshaded in that this is, in fact, exactly what Vyvyan had designed the potion to do.
Vyvyan: It's basically a cure! For not being an ax-wielding homicidal maniac.
- Firefly's River Tam is the most advanced and successful version of the psychic assassins produced by the Academy, and while it isn't stated outright, both River and the methods used to create her have all the trappings of a prototype, including uncertain technology, unpredictable side effects, and crippling flaws. Naturally, River is also insane.
- Adam from Buffy the Vampire Slayer, an almost perfect version of this trope in fact. Very first thing he does when he awakes is to kill his creator.
- In NCIS it was revealed that the Port-to-Port Killer was the first and last product of an experimental CIA training program, intended to transform servicemen into assassins. After his only sanctioned kill, he promptly went serial-killer using his spook/military training and a handy folder of fake passports.
- Final Fantasy LOVES villains with this backstory.
- In Final Fantasy VI, talking to an NPC in the Empire's capital city will reveal that Kefka was the first Magitek knight created by The Empire, and he was driven insane by the process. (Luckily, they got it right with Celes.)
- Kuja from Final Fantasy IX is this in addition to a Flawed Prototype (albeit, intentionally flawed).
- Dissidia Final Fantasy reveals that Garland, of all villains, was one. He was a Super Prototype, too; his powers were once strong enough to defeat Omega and all the summoned beasts in his world.
- In Final Fantasy VII, Sephiroth was the prototype of the Shinra program that would eventually develop SOLDIER; while he was extremely well-behaved for a time, discovering the secrets behind his creation drove him mad and turned him into the greatest threat to life the Planet had ever seen.
- Crisis Core has Genesis Raphsodos who also qualifies as a Flawed Prototype. Unlike Sephiroth, he was nuts to begin with, and only gets worse when he discovers that he was not only a failure from the project before the one that spawned Sephiroth, but also deteorating at a high rate.
- F.E.A.R. Series:
- FEAR oddly messes with this, the first prototype (the pointman) is considered a failure, the second prototype (Paxton Fettel) is the one who cause problems, but only with a little help from his mum.
- Nebilim from Tales of the Abyss: The first human replica, and utterly insane. Then again, its creator wasn't entirely stable-minded when he created it either.
- Xion in Kingdom Hearts qualifies, as the "No. I" of Xemnas' Replica project, a duplicate of Sora. The Riku Replica also arguably qualifies.
- Doctor Light was terrified at Mega Man X becoming this, which is why X was sealed for at least 30 years testing his morality.
- Inverted with Axl: Axl was a prototype to the transforming next-generation Reploids, yet he himself is actually quite sane (even if he has a slight Blood Knight nature to him), it's the mass produced versions that were insane.
- Killing Floor the clot is basically a prototype clone of Kevin's dead son. It had all the natural traits of a zombie, aggressive, bloodthirsty and is practically cannibalistic.
- The King of Shadows in Neverwinter Nights 2 might be an example.
- In StarCraft II, Spectres were a brief program run by Mengsk to create a new breed of more powerful psychic assassins, replacing the original Ghost units seen throughout StarCraft. Nova, a Dominion-loyalist Ghost, claims the project was shut down and the Spectres imprisoned because they were psychotic killing machines.
- However, if the player takes the "Breakout" mission, which has been stated to be the canonical mission, then they learn that Nova was basically lying and Spectres are no more prone to going mad than Ghosts are, if less. The real reason the project was abandoned was because the power-boost that made a Ghost into a Spectre let them blow out their Restraining Bolts.
- Prototype Jack in Tekken 1 is designed to be a super powerful robot that's gone haywire and its owner has lost control of it. The one in 2 and Tag Tournament is more of an army drone and so isn't as evil as it's just following orders.
- Alpha in Mega Man Battle Network 3 is the prototype of the Internet itself given form and AI.
- Proto Man, but only in the Mega Man animated series. In the games he's more of an Aloof Big Brother; he also has some kind of design flaw in his power plant or buster that can prove fatal, and means he has less health.
- Earl, Rusty's "older brother" from Big Guy and Rusty The Boy Robot isn't exactly crazy, but his AI is woefully incomplete and he's a very angry kid. Basically, take Atlas, Gunnery Sargeant Hartmann and Rain Man, put them in a blender and hit puree.
- Protoform X, from Beast Wars: the Ax Crazy Rampage. He was created by Maximal Scientists (attempting to duplicate Starscream's annoying ability to not stay dead) as an immortal supersoldier. What they got was a psychotic killing machine that massacred them and the rest of the colony they were on. Also, he was an immortal supersoldier.
- XL from Buzz Lightyear of Star Command was built before XR; XL had villainous inclinations.
- Robotboy had Protoboy, the titular character's older brother who was captured and turned into an Omnicidal Maniac by Dr. Kamikazi. He would go to various lengths to attempt to prove he's Professor Moshimo's best invention/kill him, including switching his motherboard with his brother so he can get close to Moshimo and later threatening to kill Moshimo in a robot factory by pouring molten titanium on him unless Robotgirl offers to take his place. While he had a penchant for coming back to life after being blown up he's supposedly Killed Off for Real in the aforementioned factory.