See text Elysia is a genus of sea slugs, marine gastropod molluscs in the family Plakobranchidae.

These animals are colorful sea slugs, and they can superficially resemble nudibranchs, but are not very closely related to them.

[1] Elysia sea slugs graze on algae and some species such as E. viridis and E. chlorotica hijack the chloroplasts for themselves.

These proteins, numbering in the hundreds, are manufactured in the cell's nucleus, and then moved into the chloroplast, enabling it to survive.

[2] There has been a study regarding a member of the genus Elysia (E. chloritica), which states that there is horizontal gene transfer when the slugs ingest the algae.