What is Pikachu's official Pokédex category in Pokémon?

Pikachu's official Pokédex category is Mouse Pokémon.

The category appears in Pokédex descriptions and refers to Pikachu's biological-style classification within the fictional Pokémon world. Pikachu is an Electric-type Pokémon, but Electric is its type rather than its category. This distinction explains why answers such as “Electric Pokémon” do not identify the requested Pokédex label.

Pikachu was designed by Atsuko Nishida and illustrated for the original games by Ken Sugimori. Its yellow body, red cheek markings, and lightning-bolt tail helped make it the franchise's best-known mascot. The anime further increased its fame by making Pikachu Ash Ketchum's partner.

Pikachu was numbered 025 in the original National Pokédex. It evolves from Pichu when friendship is high and evolves into Raichu with a Thunder Stone, although the anime famously keeps Ash's Pikachu from evolving.