Reading about this will immediately make you want to break out the Pokemon Red.

Ken Sugimori, Atsuko Nishida, and Koji Nishino, three of the brains behind the designs of all your favourite Pokemon, recently sat down to talk shop with Japanese newspaper Yomiuri. Anyone who remembers the original 151 Pokemon knows that in the first generation Pokemon either didn't evolve, could evolve once or could evolve twice. Pikachu, undoubtedly the most famous Pokemon, could only evolve once — from Pikachu to Raichu. However, that wasn't always the plan, and Atsuko Nishida revealed there was originally a design for a scary-ass third evolution stage of Pikachu with fangs and horns. "Yes. It was “Pikachu,” “Raichu,” and “Gorochu.” The Pokémon known as Gorochu bared fangs and even had a pair of horns. However, the designers confirmed that Gorochu wasn't cut because it was scary — just because the sensitivities of old gaming systems were easy to overload. "There wasn’t any problem with its appearances, but it was omitted due to matters surrounding game balance." Sadly, this means we don't even have an image of what a fully animated Gorochu would look like. The trio further revealed where the inspiration for Pikachu came from, saying that Ash Ketchum's best friend was a combination of mouse, squirrel, and daifuku (which is apparently a type of Japanese pastry).