Reddit user Smithnigel has apparently discovered how to choose your Eevee’s evolution in Pokemon GO. They posted their theory at the Pokemon GO subreddit, and in an edit gave credit to another user for posting similar information a day prior.
The method is simple, but it initially requires knowledge of a particular episode of the Pokemon anime, “The Eevee Brothers.” In the episode, three brothers each own a different ‘eeveelution;’ Flareon, Jolteon and Vaporeon; which were nicknamed Pyro, Sparky and Rainer, respectively.
“If you nickname your Eevee either Rainer, Pyro or Sparky, your Eevee will evolve into that desired Eeveelution!” writes Smithnigel. “I have tried it on a few Eevees and so have friends, and we’ve seen a 100% success rate.”
Since the original post, other users have chimed in with their success, with one user even linking video proof. Without the nickname trick, Eevee appears to evolve into either Flareon, Jolteon or Vaporeon at random, and it isn’t known how other eeveelutions will be handled in subsequent updates.
The Easter Egg of sorts is a nice nod to the original show, though Pokemon GO players should be advised that due to heavy traffic on Niantic’s servers, it would be wise to quit the app in between nicknaming your Eevee and making it evolve. This is to ensure the game properly updated your nickname. It appears that sometimes, the game does not register the changed name until after the Eevee has been evolved.