Ash's Pikachu

Ash's Pikachu is the first Pokémon that Ash ever obtained.

Biography
Pikachu is awesome.

Trivia

 * Pikachu is Ash's sole Electric Pokémon.
 * Ash attempted to evolve Pikachu with the Thunder Stone after he lost to Lt. Surge's Raichu, but he chose not to evolve because he wanted to prove that he can defeat stronger Pokémon without the need to evolve.
 * Pikachu on occasions has acted as a responsible leader of the main cast's Pokémon, mainly Ash's Pokémon.
 * In the season one episode "Showdown at Dark City" Pikachu displayed a strong fondness for ketchup. In fact, when the ketchup bottle he was carrying was smashed, Pikachu was seen crying over his smashed ketchup bottle. This could be an indication on how close Pikachu's realationship with Ash since his last name is similar to ketchup.
 * In Season 1 (Indigo League) Ash's Pikachu's favorite snack appeared to be apples.
 * He has a game of his own, Pokémon Yellow, where he is the only availible starter, and refuses to go into it's Pokeball. Instead, it follows you around. This inspired the "first-Pokémon-to-follow-you" feature on HeartGold and SoulSilver.
 * In the season one episode "Ash Catches a Pokémon", when Team Rocket was trying to steal Pikachu, Meowth accidently says that Ash's Pikachu's power exceeds the level of power he would have as a Raichu.
 * Despite using Tackle and Leer in The Double Trouble Header and Hour of the Houndour respectively, Pikachu in the games cannot actually learn these moves.
 * In the first movie, Pikachu battled a clone of itself.
 * Around all the pokemon Ash has had over the series, only Pikachu was with him all the time in all regions