In video games In
Pokémon Red and
Blue, the player learns of Mewtwo's existence by reading research notes left in the ruined Pokémon Mansion on Cinnabar Island. The notes say that a scientist discovered a new Pokémon in a
Guyana jungle, that they named it Mew, and that it later gave birth to a creature they called Mewtwo; the game's Pokédex entry states that Mewtwo was "created by a scientist after years of horrific gene splicing and DNA engineering experiments". Mewtwo proved too mighty to control, destroying the laboratory and escaping. The player is later given an opportunity to capture Mewtwo in the Cerulean Cave, which is accessible only after defeating the game's final
bosses, the
Elite Four and
Blue; in the remakes
Pokémon FireRed and LeafGreen this prerequisite was expanded, requiring the player to explore more thoroughly and record information on sixty Pokémon species before access to the cave would be granted. Mewtwo can be caught in
Pokémon HeartGold and SoulSilver in the same location as before after defeating all of the gym leaders in Kanto. The character was also the focus of a promotion and
downloadable content giveaway for
Pokémon Black and White, debuting with its signature move "Psystrike" that can also be learned by leveling up. Mewtwo also reappears in
Pokémon X and Y after completing the main story, and is one of the handful of Pokémon capable of using the new Mega Evolution mechanic, as it can transform into either Mega Mewtwo X or Mega Mewtwo Y. Mewtwo reappears in
Pokémon: Let's Go, Pikachu! and Let's Go, Eevee!, another remake of
Red and Blue, again in Cerulean Cave and is capable of Mega Evolution. Mewtwo is also obtainable alongside other past Legendary Pokémon in
Pokémon Ultra Sun and Ultra Moon,
Pokémon Sword and Shield: The Crown Tundra, and
Pokémon Brilliant Diamond and Shining Pearl. In addition to being transferable to almost every mainline
Pokémon game, Mewtwo has also made appearances in multiple spin-offs. In
Pokémon Stadium and
Pokémon Pinball, Mewtwo appears as a final boss after all competitions have been completed. In
Pokémon Puzzle League, Mewtwo, voiced by
Philip Bartlett, serves not only as the final opponent, but also as the main
antagonist responsible for the game's events. Mewtwo appears in the
Pokémon Mystery Dungeon series, featuring Mewtwo as an unlockable
player character that must be defeated before it may be used in
Pokémon Mystery Dungeon: Blue Rescue Team and Red Rescue Team. Mewtwo has been a playable character in multiple entries of the
Super Smash Bros. series. Mewtwo was originally meant to appear in the original
Super Smash Bros., but was cut due to time constraints. Mewtwo made its debut in the series in
Super Smash Bros. Melee voiced by Masachika Ichimura who reprises his role in
Pokémon: The First Movie. After simply appearing as a trophy
Super Smash Bros. Brawl, Mewtwo returned to the series as a
DLC character in
Super Smash Bros. for Nintendo 3DS and
Wii U on April 28, 2015, though it was made available to Club Nintendo members who registered both versions on April 15, 2015. In
3DS and
Wii U, its Final Smash involves it Mega Evolving into Mega Mewtwo Y and using Psystrike, its signature move in the
Pokémon games. Mewtwo also returned as a playable character in
Super Smash Bros. Ultimate for the
Nintendo Switch, where it is once again an unlockable character. In both
3DS/Wii U and
Ultimate,
Keiji Fujiwara voices Mewtwo in all languages. A new form of Mewtwo, Shadow Mewtwo, appears as a boss character in
Pokkén Tournament and has a special attack that involves it Mega Evolving into Mega Mewtwo X. Shadow Mewtwo can also be unlocked as a playable character. In addition, its normal form appears as a playable character. In augmented reality mobile game
Pokémon Go, Mewtwo is able to be battled and caught in event Raids available on select dates and times, including a different variation of Mewtwo wearing its armor from
Pokémon: Mewtwo Strikes Back - Evolution that was made available for a limited time in Tier 5 Raids in July 2019. In the
Detective Pikachu game and its sequel
Detective Pikachu Returns, Mewtwo is a major character of the plot with it being a key to the mystery behind the disappearance of the main character's father, Harry Goodman. Mewtwo also appears as a usable Pokémon in
Pokémon Masters as the partner of Giovanni, who first became playable in the first Legendary Event, "Lurking Shadow". During the first part of the Villain Arc story with
Team Rocket, "Looming Shadow of Kanto", the player could obtain Giovanni Legendary Spirit to raise the rarity of Giovanni to 6-Star EX if the player also used all 20 Power-Ups for Giovanni, which gives it a power boost and makes his Sync Move target all opponents instead of one, and then in the second part of the arc, "Spreading Shadow", the player could obtain Mewtwo Crystals to allow Giovanni's Mewtwo to evolve into Mega Mewtwo Y, which makes it even stronger and replaces the move Confusion with Psystrike until the end of the battle. In July 2023, Mewtwo was added as a playable character to
Pokémon Unite.
In anime and related media Mewtwo appears in the episode 63 of the animated series (episode 61 in the English dub) titled "The Battle of the Badge" wherein Giovanni sends in Mewtwo during his gym battle at Viridian Gym with Gary Oak. Mewtwo easily defeats all of Gary's Pokémon and is afterwards taken by Giovanni on a secret mission. In the following episode, "It's Mr. Mime Time!", Mewtwo appears briefly while Giovanni is on a video call with Team Rocket. In both episodes, Mewtwo is covered in various pieces of advanced armor and machinery which obscure its features. Mewtwo is featured as the titular main antagonist in the 1998 film
Pokémon: The First Movie. Unlike in the games, it is shown to be the creation of the criminal organization
Team Rocket, and is referred to as an enhanced clone instead of a
genetically modified mammal. After Mewtwo destroys the laboratory where it was born, Team Rocket's leader,
Giovanni, convinces Mewtwo he can help it control its powers, instead using Mewtwo as a weapon. After escaping Giovanni, Mewtwo questions the reason for its existence and declares revenge on its creators. To this end, it lures several
Pokémon trainers, among them anime series's main
protagonist Ash Ketchum, to its island in order to clone their Pokémon. Once it does so, Mewtwo forces the originals to battle their clones in an effort to determine which set is superior, while Mewtwo faces its own genetic relative, Mew. Ash dies himself to stop the fighting, though he is later revived from tears shed by both the originals and clones because of his death. Mewtwo, upon acknowledging the selflessness of Ash's sacrifice, comes to the conclusion that one's actions determine who they are and not the circumstances of their birth. Soon after having this epiphany, Mewtwo and the clones are joined by Mew as they leave to find a sanctuary, with Mewtwo erasing all memory of the events from those gathered as a final gift. In localizing the film for English-language audiences, Mewtwo's personality became more arrogant and
megalomaniacal; localization director
Norman Grossfield ruled the changes necessary, as he believed American audiences needed a "clearly evil" instead of ambiguous villain. In the film, Mewtwo is voiced by
Jay Goede (credited as Philip Bartlett) in English, and by Ichimura in Japanese. In December 2000, the film was followed by a direct sequel,
Pokémon: Mewtwo Returns, which was broadcast on Japanese television in December 2000 and released worldwide on home video and DVD in 2001. Voiced by
Dan Green in English with Ichimura reprising the role in Japanese, Mewtwo and the clones have since found peace on Mount Quena in Johto, a region which directly neighbors Mewtwo's home region of Kanto. However, Giovanni, whose memories were left intact after the first film, locates and pursues Mewtwo. Assisted by Ash and his companions, Mewtwo comes to terms with its existence and defeats Giovanni, removing any memory of itself from him and his soldiers' minds while leaving the others unaffected. As everyone departs, Mewtwo sets out on its own while the clones remain safely behind on Mount Quena. The 2006 television special
Pokémon: The Mastermind of Mirage Pokémon features a
hologram version of Mewtwo, created and controlled by the story's antagonist Dr. Yung. With help from a hologram Mew, Ash and his companions destroy the Mewtwo hologram and defeat Yung. Another Mewtwo appears in the anime special
Mewtwo: Prologue to Awakening and its direct sequel
Pokémon the Movie: Genesect and the Legend Awakened, voiced by the actress
Reiko Takashima. Compared to the original Mewtwo, this one is also conflicted about its existence, yet is more empathic to the point of not being belligerent toward humans, as shown when it protects Ash, Iris, Cilan, and Eric from the rampaging Genesect army. Unlike the original Mewtwo, this one is able to Mega Evolve into Mega Mewtwo Y; due to
Mega Evolution not being fully introduced at the time, it is referred to in the film as Mewtwo's . A Mewtwo, which was created by Mr. Fuji, appears in the anime miniseries
Pokémon Origins, which is generally based on the plot of the video games
Pokémon FireRed and
LeafGreen. As such, Red goes to Cerulean Cave, and uses the
Mega Evolution mechanic introduced in
Pokémon X and Y to Mega Evolve his
Charizard for the fight with Mewtwo, whom Red captures. Mewtwo made its
live-action animated debut in the 2019 movie
Detective Pikachu. Mewtwo also appears in the film
Pokémon: Mewtwo Strikes Back—Evolution, a remake of
Pokémon: The First Movie – Mewtwo Strikes Back, that premiered on July 12, 2019. Mewtwo from the first film appears in
Pokémon Journeys episode "Getting More Than You Battled For!". Mewtwo protects several Pokémon that had been abused by humans on Cero Island since its departure from Mount Quena. Ash recognizes Mewtwo while Goh meets it for the first time after they were saved from the waterfall. After defeating Ash and Goh in a battle, Mewtwo decides to leave Cero Island with the rescued Pokémon and teleports them back to the Cerise Laboratory, allowing them to retain their memories of the encounter.
In printed adaptations Mewtwo has appeared as a central character in several books related to the
Pokémon franchise, including novelizations of
Mewtwo Strikes Back and
Mewtwo Returns, both of which closely follow the events of the films. In December 1999,
Viz Media published the children's picture book ''I'm Not Pikachu!: Pokémon Tales Movie Special'', which featured children taking on traits of the characters from the film, including Mewtwo. In May 2001, Viz released a second children's book, ''Mewtwo's Watching You!'', which featured a shy Mewtwo interestedly watching other Pokémon play. In the manga series
Pokémon Adventures, Team Rocket created Mewtwo, but due to the insufficient amount of genetic material at hand (being just a couple of Mew's eyelashes), Gym Leader Blaine - Team Rocket's head of research at the time - had to supplement the experiment with human DNA taken from his own right arm to fill in the gaps, which led to some of Mewtwo's DNA to enter his body as well. Because of the DNA that they share, the two are unable to be separated for very long without becoming ill. Later, another Pokémon,
Entei, is able to break the bond between the two by burning away the DNA link in Blaine's arm, at which point Mewtwo leaves. It eventually helps the main character of the series, Red, fight against Team Rocket leader Giovanni and his
Deoxys. In 1998,
Toshihiro Ono was asked to write a story detailing Mewtwo's origin to coincide with the release of
Pokémon: The First Movie – Mewtwo Strikes Back. The 52-page comic, presented in the form of a flashback, ==Promotion and reception==