Mudkip, a kind of Pokémon that appeared in the handheld game series "Pokémon" developed by GAME FREAK and released by Nintendo, first appeared in Pokémon Ruby/Sapphire.

Relying on the cheeks to breathe in the water, the strength he exerts in distress is enough to crush rocks larger than himself. The fin on the head acts as a radar and can distinguish the surrounding conditions.

Source: Mudkip is based on the mudskipper or mudskipper of the Goby family, both of which are amphibious aquatic creatures. The divergent gills beside Mudkip's cheeks may also come from the Mexican blunt-mouthed newt, similar to Wubo.