The opisthobranch gastropod mollusk of the species Elysia timida is a unique example of natural evolution, as it is able to photosynthesize. The green color on its body comes from chloroplasts, derived from the algae that the animal feeds on. The cellular organelles of the algae (nucleus, mitochondria, etc.) are digested by the snail, but this is not the case with the chloroplasts, which are distributed in surface cells, that is, in places seen by the sun. Thus the opisthobranch acquires the ability to digest carbon dioxide and convert it into glucose, lipids, even proteins and supplement its nutritional needs. The little sea slug becomes almost autotrophic as all it needs is to take the necessary minerals from the environment. This phenomenon called "Kleptoplasty" is a unique evolutionary process of nature as it creates a multicellular, moving independently, photosynthetic organism, capable of producing oxygen. The size of the opisthobranch is a few millimeters and can be found in almost all greek seas (here from Paros), especially in areas with intense presence of algae.