Ash receives Pikachu at the start of the first Pokémon anime episode.
In “Pokémon, I Choose You!”, Ash arrives late at Professor Oak’s laboratory and finds that the three usual starter Pokémon have already been chosen. Professor Oak gives him Pikachu, an Electric-type Pokémon that immediately proves difficult because it refuses to stay inside its Poké Ball.
The pair begin their journey with a strained relationship. Pikachu will not obey Ash and rides on his shoulder rather than entering the ball. Their bond changes after Ash protects Pikachu from a flock of Spearow, and Pikachu uses its electricity to save them. That moment establishes the friendship central to the anime.
Pikachu was not the player’s default starter in the original Red and Green games. Bulbasaur, Charmander, or Squirtle were the available opening choices there, so viewers sometimes incorrectly transfer the anime’s setup to the games.