Pikachu follows the player throughout Pokémon Yellow: Special Pikachu Edition.
Unlike Pokémon Red and Blue, Pokémon Yellow gives the player Pikachu as the only starter Pokémon. It remains outside its Poké Ball and appears behind the player while traveling through the game world. Players can also interact with Pikachu to see reactions based on how it has been treated.
This design was influenced by the Pokémon animated series, where Ash’s Pikachu became the franchise’s most recognizable character. Yellow also changes the rival’s starter: the rival receives Eevee rather than choosing one of the traditional starter Pokémon. Several characters and events similarly echo the anime’s presentation.
Pikachu’s following behavior was unusual for the original Game Boy games and later inspired features in Pokémon HeartGold and SoulSilver. It is easy to confuse Yellow with the standard Red and Blue games, but the special Pikachu-focused presentation is precisely what distinguishes Yellow from those earlier versions.