Rhydon is widely identified as the first Pokémon designed for the original games, based on comments from illustrator Ken Sugimori. Its early concept reflects the creature designs that helped shape Pokémon’s visual identity.
Rhydon appears as Pokédex number 112 in Generation I and is a Ground/Rock-type Pokémon. It evolves from Rhyhorn and can later evolve into Rhyperior in games that include Generation IV’s evolution methods.
The “first designed” fact is about development history, not the Pokédex order. Bulbasaur is number 001, while Rhydon’s sprite and concept existed before the final numbering and roster were settled.
Because Pokémon development spanned sketches, prototypes and revisions, statements about the first design refer to the documented early concept rather than a public in-game debut. Rhydon’s appearance in the first games made it familiar even though it was not the first Pokédex entry.