If you have an Eevee in Pokemon GO [Free], and want to make sure that it evolves into one of Jolteon, Vaporeon, or Flareon, it seems as if Niantic has offered a way to do so. As discovered by Reddit users u/TheAztek and u/smithnigel and confirmed by various users trying this method, with video by u/strongscience62, these names will trigger the various evolutions:

Sparky = Jolteon
Rainer = Vaporeon
Pyro = Flareon

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This might seem random, like perhaps someone just dug up some random names and discovered that whatever RNG powers the game has those coincidentally-appropriate names trigger Eevee evolutions. But no, it's actually a really cool Easter egg on Niantic's part. The original Pokemon anime series had the Eevee Brothers, whose names were Sparky, Rainer, and Pyro. And they had Jolteon, Vaporeon, and Flareon respectively. That's really cool on Niantic's part to throw that in for the long-time fans, though who knows how long it'll work if being able to trigger specific Eevee evolutions is a balance problem. Users are claiming Vaporeon is the most powerful of the 3, but a Jolteon could easily counter one of those...
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