Shellos is a sea slug-like Pokémon whose appearance changes drastically depending on the sea it is found in. However, both forms have amorphous, slug-like bodies. Like real sea slugs, they have mantles covering the top halves of their bodies. Unlike real sea slugs, they have bulbous heads and four small feet rather than one large foot. Both forms also have black oval-shaped eyes, tiny noses, wide yellow lips, and yellow outlines around their eyes and mantles.
In the West Sea form, the underside is white and the mantle is pink. The mantle has several small spike-like protrusions on it. On its head is a ring of pink fleshy knobs resembling the gills of a nudibranch.
In the East Sea form, the underside is green and the mantle is blue. The shell has two flap-like protrusions, resembling cerata. These protrusions are lined with yellow. On its head are two white-tipped tentacles resembling rhinophores that extend away from its face.
West Sea - For the most part, it makes its home along the seashore. Its color and form differ according to its habitat and the quality of its food. East Sea - Shellos lives in the sea and feasts on plankton. The lovelier the ocean where Shellos resides, the more vibrant its color becomes.
West Sea - Purple mucus sticks to the hands of anyone who touches it. Take care, as the substance is troublesome to wash off. East Sea - The difference in color from one Shellos to another seems to be a result of their diet. No large changes can be seen in their capabilities.
Shellos and its evolution were accidentally released in Pokémon GO on April 29, 2019, but were removed shortly after. On May 17, 2019, they made their official debut along with various other Pokémon from the Fourth Pokémon generation.
