Gastrodon

Gastrodon (トリトドン Toritodon) is a /-type Pokémon introduced in Generation IV. Gastrodon evolves from Shellos starting at level 30.

Biology
A moderate-sized giant slug found in the Sinnoh region. It is the same type as Whiscash, Quagsire, and Swampert, it shows allotropic specification (same species but different appearances). The one in the West is pink & brown, and the other in the East is green and blue. Gastrodon is sometimes good in battle for its high defenses and regenerative abilities although not valued for its speed considering it is a slug. It is a type Pokémon equivalent of the first gastropod Pokémon (Slugma and Magcargo). Gastrodon evolves from Shellos at level 30.

Trivia

 * This Pokémon, along with Shellos were rumored to be the pre-evolutions of Lapras prior to Diamond and Pearl's release, but this rumor was later confirmed false.
 * Gastrodon and Shellos do however, bear a slight resemblance to Lapras.