Ellewoman

The Ellefolk are a form of Fae from Denmark, and the females are called Ellewomen. They live in the areas surrounding moors and often resemble gnomes. They appear as beautiful women from the front, but from behind have a massive hole in their back and a bovine tail. They have no heart which is visible due to the hole in the back. The Ellewoman will often begin playing instruments like a harp to further lure in the men they seek to attract. If a man can break the trance and escape being lured in, he is cursed with illness. If an animal grazes in a field where one of the Ellewoman has peed or spit, the animal will quickly waste and die, and if it is a cow then this sickness can be passed through the milk. This can be avoided if the farmers ask permission from the Ellewoman for their animals to graze.

Citations:

Maberry, Jonathan. Vampire Universe: The Dark World of Supernatural Beings That Haunt Us, Hunt Us, and Hunger for Us. United States, Kensington Publishing Corporation, 2006.