Life has certain rules and patterns. Plants, with their incredible ability to harness the sun’s energy, don’t go roaming around. They don’t need to. But animals, lacking the wondrous power of photosynthesis, do. They trot, slither, flap. They seek out plants and they eat them.

They most certainly do not photosynthesize, the animal playbook would seem to dictate. That’s a plant’s role.

But one small sea slug does not care for such rules, thank you very much.

These animals, Elysia chlorotica, which live off the U.S. East Coast, are not merely content to glide about munching algae. Instead, they steal the molecular engines that allow plants to harvest solar energy. The slugs take up these mini-machines, called chloroplasts, into their skin,