Pokemon Season 13 - Episode 635 – Last Call, First Round!

Ash and friends meet up with a trainer with two Dittos — one is normal, the other one is shiny - who asks Ash to battle her. Without much of Pokémon knowledge she makes the wrong choice of Pokémon in Ditto's transformation, Ash's Infernape beats her Ditto which transforms to Infernape, and Ash's Pikachu beats her other Ditto which transforms to Piplup and Pikachu. Brock helps her about the Ditto's transformation and knowledge on other Pokémon. Finally the team arrives in Lake Valor for the Sinnoh Grand Festival.