Elysia serca
 Elysia serca the seagrass elysia or Caribbean seagrass elysia is a species of sea slug a marine gastropod mollusc in the family Plakobranchidae. Although this sea slug resembles a nudibranch it is not a nudibranch; it belongs to the clade Sacoglossa the sap-sucking sea slugs. It was first described by Marcus in 1955 from specimens found in Brazil.