Manta ray, which is a cartilaginous fish, also known by its resounding nickname, “devil ray”. Although it is large and the largest species of ray, it is very friendly to humans. It is called "devil fish", because it looks scary, with a pair of head fins like the devil's horn that used to get rid of obstacles and predation, and because they like beating the bottom of the boat, or dragging the boat with the head fin, the fishermen thought the devil was at work, so they called it devil fish.