Why are zombies called zongzi in "Tomb Robbers Notes", and why are zongzi said to be afraid of black donkey hooves?

I read Tomb Raider Notes last year. The zongzi in it refers to dead people, people who mutate into zombies. It should be just a dialect saying, or it comes from the previous legend. Qu Yuan died. At that time, the people were afraid that his body would be eaten by the fish in the river, so they wrapped rice dumplings and threw them into the river to feed the fish. Black donkey hooves are black-haired donkey hooves. The book says that Zongzi is afraid of this, but it is not clear whether it really has such a use in reality.