Mini-Dit is Duplica's second Ditto, it was caught shortly after Duplica parted ways with Ash and his friends.
Mini-Dit seems like a normal Ditto, but Duplica claims that this Ditto has a problem, which she even got Nurse Joy to check out to see if there was something wrong. Nurse Joy told her that nothing was wrong with her Ditto and that it was healthy and happy. However, Duplica still said something was wrong with it. To show what it was, she made Mini-Dit transform first into Pikachu, and then into Togepi, nothing was wrong and it transformed normally, but Duplica then told them to bring out a large Pokémon. Brock let out Onix and Duplica told Mini-Dit to transform again, it did, but it was only seven inches tall. Duplica told them that Mini-Dit could transform into small Pokémon just fine, but it couldn't transform into bigger Pokémon, it could only transform into the smaller versions of them instead. Duplica hated this and tried to fix it, but after rescuing Mini-Dit from Team Rocket, Duplica came to terms with Mini-Dit and accepted its size. Duplica then vowed to find and catch different Ditto, all with different quirks and ways of transforming until she had a whole team of odd Ditto.