Green Elysia - Elysia viridis

''Elysia viridis'', the sap-sucking slug, is a small-to-medium-sized species of green sea slug, a marine opisthobranch gastropod mollusc in the family Plakobranchidae.

This sea slug resembles a nudibranch, but it is not closely related to that clade of gastropods. It is instead a sacoglossan.