Ash Ketchum and his friends first encountered
Duplica's Ditto when they ran into Imitehouse to get out of the rain.
Ash Ketchum's attention quickly turned to a 'Pikachu' noise behind him and he was surprised to see another Pikachu beside his own
Ash's Pikachu.
Misty thought the 'Pikachu' was cute and she picked it only to be surprised by its odd looking face.
Misty quickly dropped
Duplica's Ditto as she didn't know what's wrong with the Pikachu.
Brock's first reaction was that it was new kind of Pikachu after he examined it and
Ash Ketchum tried to capture it but
Duplica stopped him by throwing a Poke ball at his Poke ball.
Duplica was training her Ditto which was having problems transforming perfectly. Her Imitehouse theater wasn't getting any patrons because they didn't want to see a Ditto that couldn't transform perfectly. Team Rocket appeared and stole
Duplica's Ditto and tried to get it to transform. It wasn't until
Meowth threatened to use its claw on
Duplica's Ditto that it finally was able to transform properly.
Duplica's Ditto tried to transform again and was able to transform perfectly from that point on.
Duplica's Ditto can also transform into objects, not just Pokémon. It has been seen transforming into a book, a picture and a canon.