At the beginning of the Song Yuanjia era (424-53 CE), a native of Fuyang surnamed Wang set up a crab-catching weir in an empty ditch. At dawn he went to look at it, and saw the end of a wooden casket, more than two chi (60cm) long, which had split the trap. The crabs had all escaped. He mended the weir, removing the casket and placing it on the bank. When he went to check on it the next day, he found the casket back in the weir, which was ruined in the same way. Wang mended the weir once more. When he went to look again, what he saw was the same as when he had started. Wang suspected that this piece of wood was a supernatural entity. He therefore put it in his crabbing basket, tied this to his carrying pole and returned. He said to himself: “When I get back I should chop this up and burn it.” Three li short of the house he heard a sudden movement, and turned his head to find that the wood had transformed into a thing with a human face, monkey body, one hand and one single foot. Addressing Wang, it said: “By nature I am very fond of crabs, so I entered the water and destroyed your crabbing weir. We have both already suffered greatly, and I hope the gentleman can forgive me, opening the basket and letting me out. I am a mountain spirit, and we should help one another; I could spread your weir wide and wait for your crabs.” Wang replied: “You bully and abuse people, but that changes now. Your crimes require a death sentence.” The thing turned and stamped, begging to be released, and asked over and over what Wang’s given and family names might be. Wang turned his head but refused to answer. As they came closer to the house, the thing said: “So you won’t release me, and you won’t tell me your name. There’s nothing for it but to await execution.” When Wang arrived at home, he kindled a fire and burned the thing. Afterwards all was still and there was no more strangeness.
Local customs call such things ‘mountain elves’, and report that, if they know a person’s family and given names, they can cause harm to that person. They thus ask with great persistence, in order to cause injury and to free themselves.
Li Fang 李昉, et al., Taiping guangji 太平廣記 (Extensive Gleanings from the Era of Great Harmony), 10 vols (Beijing: Zhonghua shuju, 1961), vii, 323.2560:
 This term is shanxiao 山魈.