Poliwag

Poliwag (Japanese: ニョロモ Nyoromo) is a Water-type Pokémon introduced in Generation I. It resembles a blue, spherical tadpole with large eyes and pink lips. Its most notable feature is the black and white swirl on its abdomen, which is actually its internal organs showing through its semi-transparent skin. Poliwag has newly developed legs, making it clumsy on land and preferring to swim. It is typically found in freshwater ponds and lakes, feeding on plants on the lake bottom. Poliwag evolves into Poliwhirl starting at level 25, which can further evolve into Poliwrath with a Water Stone, or into Politoed when traded while holding a King's Rock. Poliwag has appeared extensively in the Pokémon anime, manga, and games, and is one of the iconic early-generation Pokémon.