Eevee

Eevee is a Pokémon introduced in Generation I. It is famous for having many different choices for an evolution, with a total of eight, the most out of any Pokémon. It can evolve into: Eevee's branched evolutions are collectively referred to as Eeveelutions, a fanmade term that was made official in the strategy guide of Pokemon Stadium 2. Its category is the Evolution Pokémon. Each one of the Eeveelutions has a different type.
 * Vaporeon with a Water Stone
 * Jolteon with a Thunder Stone
 * Flareon with a Fire Stone
 * Espeon when leveled up with high friendship during the daytime (or in Pokemon XD, when leveled up with a Sun Shard in the bag)
 * Umbreon when leveled up with high friendship during the nighttime (or in Pokemon XD, when leveled up with a Moon Shard in the bag)
 * Leafeon when leveled up near a Moss Rock
 * Glaceon when leveled up near an Ice Rock
 * Sylveon when leveled up with a Fairy type move and 2 Affection hearts in Pokémon-Amie

Eevee is also the player's rival's Starter Pokémon in Pokemon Yellow. It was originally intended to be given to the player, but the rival took it first, leaving the player with a sucky Pikachu that can't even evolve. Good luck beating Brock's gym when his Geodude and whatnot are immune to all of Pikachu's electric attacks. Why they didn't let Pikachu evolve... makes sense but it still sucks.