In its natural state, Ditto is a light purple or magenta free-form blob with vestigial facial features. It also appears to have two vestigial, handless 'arms' protruding from its body.
It is capable of transforming into an exact replica of any physical object, including its form and abilities. However, if Ditto tries to transform into something based on memory, it may get some of the details wrong. Each Ditto has its own strengths and weaknesses when it comes to transforming. The anime and the TCG have shown that occasionally a Ditto cannot change its face. Ditto will also be unable to remain in a transformed state if it starts laughing. When two Ditto meet in the wild, they will attempt to transform into each other. Ditto will also transform into a rock when sleeping to avoid attack. Ditto is never far from civilization or people.
Ditto debuted in Ditto's Mysterious Mansion. Duplica and her Ditto used to perform for people, but the two had not had an audience since people saw that Ditto could not change its face. Ditto fixed that problem near the end of the episode, when it was captured by Team Rocket.
Duplica found another Ditto sometime before Imitation Confrontation, which she nicknamed Mini-Dit. This second Ditto could transform into an exact mirror image of anything, but it could not change its size.
Duplica and her Ditto are seen in The Electric Tale of Pikachu. Finding Ditto appealing, Misty decides to capture one of her own, but the plan is called off when Pikachu goes missing. Ditto also featured in a minicomic in which it transforms into Ash, harasses Misty and thereby getting Ash into a lot of pain.
In Tauros the Tyrant, Ditto is one of the members on Green's team. As a master of transformation, Green uses Ditto extensively in her schemes, such as morphing over her face to disguise her appearance (like when she infiltrated the Silph Co. building disguised as Sabrina), camouflaging into its background for subterfuge, as well as forming a protective shield with Green's umbrella.
Ditto was originally intended to be one of the Pokémon randomly released from a Poké Ball. It would have transformed into a copy of the user's character and aided them in battle. However, processing problems forced its removal before the game's release. Ditto can be still be unlocked through the debug menu (which is only accessible through the use of Action Replay), though it does not do anything other than give 7-8% damage to those who touch it.
As for its official status, Ditto only appears as a random trophy and as a cameo in the Tournament Mode menu. In Winner Out or Loser Out tournaments, holding down L and R and pressing A will give the player a random character and color. The usual character image will instead be taken by a picture of Ditto.
Every Ditto has the ability to copy a Pokémon's entire cell structure in an instant and become its exact replica. They're terrible at remembering techniques, but when they use Transform, they temporarily learn all of their foe's moves. If a Ditto starts to laugh, it weakens and can't hold its transformation.
Ditto appears as a Pokémon summoned from the Poké Ball, where it uses Transform to duplicate the shape of the summoning character while still maintaining its own color. It then attacks opposing fighters.
Pokémon Pinball: Ditto appears on the Red Table blocking the evolution cave, once the evolution arrows are lit, it moves out of the way, allowing the player to evolve one of the Pokémon they have captured.
Pokémon Trozei!: Ditto serves as a "wild card", meaning it can Trozei with any Pokémon and must be used to get rid of Jammer Balls. One will appear when a Trozei is made with more Pokémon than necessary and multiple appear at the beginning of a new round in Endless and Forever mode to clear out the remaining Pokémon.
Ditto is the only Pokémon to date with a catch rate of 35. However, in Generations III and IV, if Ditto transforms into another Pokémon, its catch rate will become that of the new Pokémon.
Ditto and Manaphy are the only Pokémon that are both able to breed yet unobtainable through breeding. Ditto, however, is the only one of the two that is not available at level 1 legally (legitimately the lowest level it is able to be is 10, in Generation II and its Generation IV remakes.
In Pokémon Snap, Ditto takes the form of Bulbasaur in the Cave stage. The player can cause them to return to their Ditto form by hitting them with an object. When the player takes their picture, Ditto has the same eyes when it is transformed as when it is not. This trait is shared by Duplica's Ditto in the anime, although it was understood that this was not natural. Ditto cards from the EX Delta SpeciesTCG expansion and the Clefairy Ditto that may appear in the Veilstone Game Corner's slot machines also have this trait.
Ditto is one of two Pokémon to have two different species-specific Stat-enhancing items associated with it, the other being Clamperl. Ditto's two associated items, the Metal Powder and Quick Powder, seem to be the same colors as Ditto's normal and Shiny forms, respectively.
In Pokémon Rumble, since Transform was not programmed into the game, Ditto can only know Struggle. Since PP does not exist in Rumble, this makes Ditto the only Pokémon in Rumble that can use Struggle. However, Transform does exist in Pokémon Rumble Blast, so Ditto has a move.
Ditto is the most common Pokémon in Pokémon Trozei!, appearing in every area. This is due to its ability to transform, enabling the player a way to advance further if no links are available before Ditto appear.
Ditto shares several aspects with Mew: the move Transform, the same Shiny blue and normal pink color, perfectly balanced base stats, and its weight of 8.8 lbs. (4.0 kg).
In Pokémon GO, Ditto appears in the wild disguised as other Pokémon. After being caught, it will reveal its true form. At one point, a large amount of Ditto were seen disguised as the then-unrevealed Mythical Pokémon, Meltan.
In Generation I, if the player manages to capture an 'M (00), it will still be in battle with the player, and the battle will not end. Catching 'M (00) again results in the second one becoming a Ditto of the same level.
The primary method of the Mew glitch involves having a wild Ditto transform into the player's Pokémon, as this copies the Special stat, which is used to modify the species of Pokémon encountered.
Transform assumption glitch
In Generations I and II, any Pokémon that uses Transform is regarded as a Ditto in its new form; this means that if the player catches a Mew or a glitch Pokémon which has used the move Transform, or a Pokémon which has used Transform via Mirror Move, instead they will obtain a Ditto. Mew turning into Ditto was not an issue, because wild Mew could not have been legitimately encountered. This system was later changed in Generation III, where wild Mew could be legitimately encountered.
In the sixth issue of Best Buy's @Gamer magazine, Game Freak developers Junichi Masuda and Ken Sugimori revealed that Ditto was originally based on the iconic smiley face. Its eyes and mouth are exactly like ":)", which is an emoticon representing the smiley.
Additionally, Ditto strongly resembles an amoeba, a single-celled organism with no definite shape. This may emphasize its ability to alter its cellular composition. This could also explain why Ditto is unavailable through breeding, since single-celled organisms reproduce differently from multi-cellular plants and animals. It also could partially be based on an undifferentiated cell, a cell in the body that can change into any other cell by sampling it. It could also have been based on a blob.
Ditto's name is the English word ditto, meaning "that which has been said before" (itself from Italian, where it means "having been said"). It was also a brand name for spirit duplicators, and came to mean copies of master documents created by those duplicators.
Metamon is a combination of metamorph and monster. Alternatively, Meta as a prefix can mean "all-encompassing," which Ditto's Transform move does do to Pokémon.