Ash's Pikachu

Ash's Pikachu was Ash's first Pokémon, given to him by Professor Oak. Though Pikachu didn't like Ash at first, Ash demonstrated his willingness to sacrifice himself for Pikachu, and they became fast friends. Pikachu, who is rather independent minded in general, believes that he is strong enough without evolving and refuses to evolve into a Raichu. Pikachu is implied to being a male, but is rarely addressed with a gendered pronoun. If a Yellow version Pikachu is traded to Silver, Gold, or Crystal, that Pikachu (since Yellow version is loosely based off the anime) is usually male.

Early in the series, Pikachu was given an operation to increase the strength of the electric sacs in his cheeks in order to beat the first gym leader, Brock. Despite this, Pikachu can also get a cold and go out of control when it cannot release its electricity. Most notably, exposure to a magnetic field will cause Pikachu to get a cold. This has been done to Pikachu twice in the series, both times by Team Rocket: the first time, Pikachu was cured when the extra electricity was used in attacks against a group of Grimer and Muk, and in the second time, Pikachu was inadvertently cured by one of Team Rocket's battery robots, which subsequently overloaded and exploded.

Many of the Pokémon animated shorts with all-Pokémon dialogue have featured Pikachu as the main character, and as the main voice of reason. As such, Pikachu is often a leader, helping to break up conflicts among other Pokémon.

Like many other Pokémon, Pikachu communicates only by saying syllables that are in his own name. His most common sentence is "Pika-pika". When he wants to talk to Ash, he says "Pika-pi," which sounds similar to "Satoshi" (Ash's Japanese name), and it refers to Togepi as "Pipipi", probably because in Japanese, "pii" means "little".

The phrase "Pika-pika" is often considered funny, particularly to Japanese speakers' ears. The Japanese expression "pika-pika hikaru" means stroke of lightning; it is also used to denote a small bald spot on the very top of the head still surrounded by hair.

Pikachu is voiced by Ikue Ootani in all versions of the anime, except in early episodes of the English dubbed series, in which Rachael Lillis provided the voice in cases where another character's voice overlaps Pikachu's. A running gag is how he burns all main female character's bike with Thunderbolt, which, in turn results in that girl following Ash, except for Iris following Ash after she and Ash bumped into each other. Pikachu also has a fondness for ketchup, which is seen multiple times in the anime.

Known Moves
+This shows all moves that have been used that have been used recently.
 * Agility
 * Iron Tail+
 * Quick Attack+
 * Thunder
 * Thunderbolt+
 * ThunderShock
 * Volt Tackle+
 * Double Edge

Trivia

 * In the season one episode "Showdown at Dark City" Pikachu displayed a strong fondness for ketchup (which is ironic considering his Trainer's last name in the English version is Ketchum).
 * Pikachu temporarily joined Team Rocket, because of his amnesia.
 * In Season 1 (Indigo League) Ash's Pikachu's favorite snack appeared to be apples.
 * Also in Season 1, Pikachu once swallowed an apple whole, requiring him to go to a human hospital, for there was no Pokemon Center nearby.