What is the hook that Luna Louro Goode said in Harry Potter?

Hooks, which look like maggots, are thicker than maggots and are black. Adults have 5000 teeth, children have 3000 teeth, the tail has a sickle-shaped hook, and there are three eyes; Life span is about 20 years. Often grows on mistletoe. It was discovered by the great magician Avery Ji Gu in a place called Migu Village in the south, so it was named Migu Hook. Avery Ji Gu was unwittingly hooked by Migu and died three days later. Since then, only luna lovegood's family has found it. The lovegood family once mentioned it in the magazine they edited, playing the devil's advocate. But there is actually no evidence to prove its existence.