"the Bean Sidhe, the banshee"

The Banshee, is usually seen as an omen of death as they are said to be heard wailing when somebody is soon to die.  Sometimes they are depicted as ugly hags but they can also take the form of beautiful women.  Often described as wearing white or pale grey, they have long hair which they brush with silver combs, a detail which makes them akin to mermaids in some tales.