Traditionally some Irish families had a banshee associated with them, and the banshee might make an appearance before a death in the family. The banshee is particularly well known for a mournful cry or wail by which this death is heralded. She is invariably dressed in white, with long fair hair which she brushes with a silver comb.
Compare: La Llorona, Bloody Mary Worth
For information on the X-Men comic book character, see Banshee (comics).