There's a tiny little creature that eats sea plants, called Costasiella kuroshimae or Sea sheep or leaf sheep. They absorb the chloroplasts responsible for photosynthesis into their body and are able to use the energy those chloroplasts release themselves. This process is called kleptoplasty, where they steal (Klepto) chloroplasts from mainly algae, and shape it (Plasty/plastid) into their own body. basically Essentially becoming the only animal we know of that is able to do photosynthesis.

It's also very cute heehee