Rhydon was the first Pokémon created by Game Freak, according to documented franchise history.
Rhydon is a Ground/Rock-type Pokémon numbered 112 in the National Pokédex. It first appeared in the original Pokémon games and evolves from Rhyhorn when Rhyhorn reaches level 42.
Its design is built around a heavily armored, rhinoceros-like creature with a drill-shaped horn. Rhydon’s bipedal body and powerful silhouette helped establish the bold, readable visual style used for many early Pokémon designs.
This fact is sometimes confused with Pokémon’s mascot history. Pikachu became the best-known character internationally, while Bulbasaur is the first entry in the National Pokédex and Mewtwo is the final numbered species in the original Kanto Pokédex. None of those facts changes Rhydon’s documented status as Game Freak’s first created Pokémon.