Please change it to the newer version
Duplica's Ditto is not only Duplica's partner Pokémon, it is also her trademark Pokémon. It appeared in IL037: Ditto's Mysterious Mansion.
Biography
Ditto's little problem.
Ditto is Duplica's partner Pokémon. It can copy any Pokémon it goes up against. At first it had a slight problem: Every time it copied a Pokémon, Ditto always kept its own face. It was captured by Team Rocket to be transformed into a Dratini. However, it has a little fun at Jessie's expense. After being threatened, it molded its face into Meowth's when it imitated him, a perfect match. After a touching moment, Team Rocket "gave" Ditto back but Duplica could tell it wasn't Ditto. After getting it back, Duplica and Ditto said their goodbyes to Ash and co.
It appeared again in JE058: Imitation Confrontation, along with Mini-Dit, its "little brother".