Are there any advanced and complex multicellular animals that have chloroplasts inside their bodies or under their skin?
Not that I know of as their own chloroplasts, but there are more complex multicellular animals out there that pinch the chloroplasts from plants. Quite a few examples are in the cnidarians; that’s jellyfish. A little freshwater jellyfish called hydra pinches chloroplasts out of green algae and keeps them in its own gut. It lets them photosynthesise and nicks the sugars that they produce. So there are animals that trick plants out of their chloroplasts.