Elysia are a Genus of sea slugs that graze on algae. Some species hijack the chloroplast from the plant matter, using it to coat the inside of their digestive tract and allowing them to survive on photosynthesis. This chlorophyll affects their colour, making them the vibrant green. Elysia are hermaphrodites, and are able to self-fertilise, but do so very rarely, preferring to mate with another individual. Eggs are laid in a long string, and these hatch into a shelled larva.