It is recorded in the article "Linyuan Seeing and Hearing" Natural History - Examination of Monsters;
In the land of Nanyi, there is something that looks like a human but not an animal in the ancient forest and sea. Its name is Shark. Shark is the essence of water. It likes yin and good water, and hides in mountains, rivers and lakes. It is said that a hunter once encountered a hunter who was struck by an arrow in his heart and was not dead, so he killed him with a knife. Then he cut off his head and dissected his body bones to find out the reason for his immortality. It turned out that his heart and bowels were very different from normal and were born on the right side, so he could not be killed by ordinary methods.