"But after the mortal violent death, there is a kind of resentment in my heart. This kind of anger is invisible and colorless, and it will take many days to get rid of it. If it happens to be condensed by many grievances, this anger will gather near the insect nest. Insect ants, butterflies and bees will mutate into sperm and feed on adult men full of yang. Every time they eat a person, they will evolve into cocoons, and every time they lose their skin, their patterns will be more beautiful.
"This is called mourning, also called corpse wall, and it is not surprising that there are many records in Taoist classics.