Banshee

From Hpwiki

A Banshee is a human-shaped female creature with long hair, reaching to the bottom, and with little more than a skeleton inside. Its shriek is ear-piercing and very frightening. It is said in Irish folklore that some families has a banshee, and only members of that family can here her cry. To hear this cry is a very bad sign, meaning that someone in you're family will die soon. Seamus Finnigan had a banshee for Boggart in Prisoner of Azkaban. Gilderoy Lockhart claimed to have expelled the Bandon Banshee, but in reality this was done by an unattractive witch who lost her memory of the incident to Lockhart's Memory Charm.