Pikachu is the player's only starter Pokémon in Pokémon Yellow: Special Pikachu Edition.
Pokémon Yellow was an enhanced version of the first-generation games designed to resemble aspects of the Pokémon anime. Instead of choosing Bulbasaur, Charmander, or Squirtle at the beginning, the player receives Pikachu from Professor Oak.
Pikachu follows the player on the overworld and has a happiness-based relationship with the player. It also refuses to stay inside its Poké Ball, a feature that reflects its anime-inspired personality.
The rival's starter in Pokémon Yellow is Eevee, which is why Eevee is sometimes mistakenly given as the player's answer. Bulbasaur, Charmander, and Squirtle can still be obtained later, but none is the initial starter.