Shellos

Shellos is a Water-type Pokémon.

It evolves into Gastrodon starting at level 30.

Shellos have two different appearances: West Sea (pink and white) and East Sea (blue and green), found on the respective sides of Sinnoh's mountain range.

Biology
Shellos is a slug-like Pokémon whose appearance changes drastically depending on the sea it is found in. However, both forms have a shell-like back and an amorphous lower body. Both forms also have yellow lining around their eyes, mouth, and back.

In the West Sea form, the underside is white and its shell is pink. The shell has several small spike-like protrusions on it. On its head is a ring of pink fleshy knobs resembling flower petals that spike up.

In the East Sea form, the underside is green and its shell is blue. The shell has two flap-like protrusions. These flaps are lined in yellow. On its head are two white-tipped knobs resembling horns that extend away from its face.