There Is a Slug That’s Part Plant

The tiny Costasiella sea slug looks like something from a fantasy world, with a body covered in green, leaf-shaped structures that make it resemble a miniature underwater plant. Also called the leaf sheep slug, its unusual appearance helps it blend in with the algae it eats — and the chloroplasts it steals from that algae are what lend the slug its green color.

Chloroplasts are the structures plants use to capture sunlight and produce energy. Through a process called kleptoplasty, the slug can store those chloroplasts inside its own body and use them to produce some energy from sunlight. While the leaf sheep does not become a plant or photosynthesize exactly like one, its ability to use plant parts in this way makes it one of nature’s best examples of an animal with plantlike abilities.