Ash's Pikachu has avoided evolving for the entirety of Pokémon's decades-long run — but why? The anime aired its first episode in Japan on April 1, 1997, and focused largely on Ash Ketchum's quest to become a Pokémon master. Throughout this journey, his Pikachu resisted evolving despite having several opportunities to make the change.
The first of Ash's Pokémon to evolve was his Caterpie in the episode «Ash Catches a Pokémon.» Caterpie made the decision to evolve into Metapod after a battle with
Read more on screenrant.com