For example, theres this sea slug that I found out eats algae, which is normally exactly what you think is usual for an underwater marine animal, but guess what?
IT USES THE CHLOROPLASTS FROM THE ALGAE AND THEN GAINS THE ABILITY TO USE PHOTOSYNTHESIS AS A SLUG VIA ABSORBING PLANTS
This post is 2 years but old but only about 1% of all the species of animals and plants that ever lived have been found.