Which Pokémon species did Atsuko Nishida originally design?

Atsuko Nishida originally designed the Pokémon species Pikachu.

Nishida worked on Pikachu during development of the first Pokémon games after lead designer Ken Sugimori sought a cute Electric-type creature. Pikachu’s initial design was created to fit the technical limits of the original Game Boy, including its restricted color capabilities.

The final artwork was completed by Ken Sugimori, while Pikachu’s design and development involved several members of the Game Freak team. Pikachu was conceived as a small, appealing creature rather than as a traditional powerful monster, helping it work well in merchandise and animation.

Pikachu was not initially the only mascot candidate. Clefairy was also considered for a prominent role, but Pikachu was ultimately selected for the anime because its design appealed broadly to children and could represent players regardless of which starter Pokémon they chose. Pikachu later became the franchise mascot, while Pichu was added as its pre-evolution in Pokémon Gold and Silver.