Ditty first appeared in Tauros the Tyrant. Green substituted it for Blasty during the battle with Team Rocket in Celadon City when Blasty was trampled by their Hitmonlee and Ken's Machamp. As soon as Ditty was sent out, Team Rocket became amused by it as they found it to be weak. Ken then sends out his Tauros in order to knock Ditty and Green out. However, Red came to Green's rescue but unfortunately, Ditty fell off the cliff. Ditty, however, transformed into Ken's Tauros which also fell off the cliff. As Ditty transformed into Tauros it took control of Team Rocket's Pokémon and forced them to attack their Trainers, allowing Green and Red to get away. After Green revealed that she gave Team Rocket the fake disc and that she had the real one, she sent out Ditty again to take on the form of a Mew in order to keep Ken and Team Rocket occupied. With Ditty distracting them, both Red and Green go off to search for Mew. However, Ken managed to weaken Ditty using Jynx before the two Trainers were able to capture the real Mew.
In Zap! Zap! Zapdos!, Ditty, disguised as Blasty, was sent out to battle Sabrina's Kadabra when the Psychic-type created an illusion of a giant tower outside of the one Green was in. Unfortunately, Kadabra was too quick for Ditty as it used Teleport to dodge and knocked it down with Psychic. With Ditty immobilized, Kadabra was about to finish it off until Green revealed that the Blastoise Sabrina was fighting was merely a transformation coming from her Ditty. Blasty was then sent out and defeated Kadabra.
In Clefabulous Clefable, Ditty disguised itself as Green's right hand when she was fighting against Lorelei, tricking her into believing she had bound Green and Sabrina together. Ditty later fell off, making Lorelei believe that Green's hand had been destroyed with the destruction of her ice doll. However, Ditty soon turns back to normal and wrapped up Lorelei and her Jynx, immobilizing them.
In Now You See Me..., Green and her team are attacked by a Deoxys, with Red and Blue saving her and bringing her to the Pokémon Network Center. After the two of them leave to go to Two Island Ditty sneaks into Red's backpack. While the two went off to train Ditty became friends with Ultima and filled her in on the situation by using Transform to communicate. When Red and Blue finished their training Ditty was waiting for them Transformed as Deoxys, allowing the two to get an understanding of what they were fighting.
Ditty is a very happy-go-lucky Pokémon, and is often seen enjoying whatever it is doing. Ditty tends to not get serious until there is a threat to its Trainer, and then becomes very concerned and stoic. Because Ditty's only move is Transform Green does not use it in battle very often and uses it instead to help in her ability to trick people. Besides transforming into other Pokémon, Ditty can also change into items, as well as a facial mask to help Green disguise herself as someone else, such as Sabrina.