Eevee’s genetic code is irregular, and it may mutate if exposed to radiation from elemental stones. In “The Battling Eevee Brothers” Ash and friends find an Eevee tied to a tree. They notice its tag and promptly return it to its owner, Michael, whose three brothers are forcing him to make the Pokémon evolve. After a confidence-building battle against Team Rocket, Michael decides to let Eevee just be itself.
First appearance: Episode 40 — “The Battling Eevee Brothers”
