Black Annis is a figure from English folklore known for her tendency to devour children.
The image of a creature who seeks out and destroys children is fairly common. The motif extends throughout world mythology, and provides a convient way of encouring good behavior in children-be calm or Baba Yaga will get you, be good or Black Annis will eat you. The motif is so strong in fact that it is even replicated in modern urban legends.
While the historical basis of the story seem to be unknown (theories range from historical evolution of actual women to a type of pre-historical goddess worship being misremembered-though it should be noted that this particular theory has fallen into disrepute) the legend of Black Annis seems to be fairly localized to England. Black Annis lives in a cave in the woods where she flays the skins off of children and wears their skins as a skirt. She eats those children-children who she has stolen from their houses using her long, sharp claws.
(BPAL does a Black Annis blend. I happen to quite like it).