I read the notes on grave robbery last year. The zongzi in it refers to a dead person who has mutated into a zombie-like person. It should be just a dialect saying, or it originated from a previous legend. When Qu Yuan died, the people were afraid that his body would be eaten by fish in the river, so they wrapped the zongzi and threw it into the river to feed the fish. A black donkey's hoof is a donkey's hoof with black hair. It is said in the book that Zongzi is afraid of this. It is not clear whether it is really useful in reality.