In the old language of Gaelic, this Irish spirit was called Bean-sidhe. She is a ghostly woman, dressed in a white shroud, her hair flowing behind her, her hands extended before her like claws. She is usually described as old and ugly, but it isn't her appearance you need to fear, it is her wail.
The banshee is a bad omen, if her hear a long, shrill scream echoing out in the hills, it means someone will soon die. Banshees were usually thought to be attached to old families, but no one is safe from her song.
Banshees really ought to be featured in more horror films, because they are downright creepy. The only movie that I can think of is a silly but beloved Disney movie from my childhood, Darby O'Gill and the Little People, starring a very young and strapping Sean Connery.
These deathly hags are one of my favorite among folklore, I even have a published story about a banshee entitled, "She Comes to Call". You have to purchase the magazine to read it, but I'll provide the link HERE in case you should wish to do so!
~by Marie Robinson