The unused planned third evolution of Pikachu was called Gorochu.
In the original development of Pokémon, Pikachu’s evolution line was planned to continue beyond Raichu. Gorochu was described as having large fangs and horns, but the character was removed before the final games were released.
Pikachu therefore became a two-step line in the finished first-generation games: Pichu was not introduced until the second generation, Pikachu evolved into Raichu, and Gorochu never became an obtainable species. Because Pichu was added later, fans sometimes mistakenly identify it as Pikachu’s unused third-stage evolution.
The removal was connected to development constraints and decisions about the number of Pokémon that could fit in the original Game Boy games. Gorochu is a development-era name rather than an official species in the released National Pokédex.