Astounding Biology

According to LiveScience┬áthese slugs have found a surprising way to make sure they meet their nutritional needs. The green sea slug appears to be part animal, part plant. It’s the first animal discovered to produce chlorophyll the plant pigment needed for photosynthesis. The slugs seem to have taken the genes for chlorophyll production from algae that they’ve eaten. “This is the first time that multicellar animals have been able to produce chlorophyll,” Pierce told LiveScience.The sea slugs also steal tiny cell parts called chloroplasts, which they use to conduct photosynthesis. The chloroplasts use the chlorophyl to convert sunlight into energy, just as plants do, eliminating the need to eat food to gain energy. “We collect them and we keep them in aquaria for months,” Pierce said. “As long as we shine a light on them for 12 hours a day, they can survive [without food].”

https://www.livescience.com/6030-surprising-sea-slug-plant-animal.html