Eevee is a Pokémon, which is #133 in the Pokedex. It evolves into 8 different Pokémon; Vaporeon, Jolteon and Flareon were the first. In Generation 2, Espeon and Umbreon became available. In Gen 4, Leafeon and Glaceon also became available. Gen 6 introduced Sylveon. Go look them up on Bulbapedia, the Pokemon Encyclopedia, online.