With the Thunder Stone, it will evolve in to a Jolteon, an electric Pokemon. With a Water Stone, it will evolve into a Vaporeon, a water Pokemon. If you use a Fire Stone on it, it will evolve into a Flareon, a Fire Pokemon. I think Flareon is the best because of its very high attack and special. There is only one Eevee in the game and you can not reverse its evolution, so choose who you want carefully.
Some people say their is one, but they just do it for attention.
They are lying again. If you do not believe me, you can e-mail Nintendo. The codes will replace the original item in the slot that you put the code in. For these codes the xx are the blanks that you put the 2 letters in for the code. The xx are the blanks that you put the 2 letters in for the code.