The word huldra comes a Scandinavian word “hidden” or “secret.” This word also lies behind the Icelandic term huldufólk, a euphemism used to avoid speaking directly about elves. Huldras are not the same as the bright and benevolent elves of Norse mythology, however. They are, in fact dangerous and seductive woodland sprites.
Huldras appear as stunningly beautiful women who are sometimes dressed in simple peasant garb. They are usually depicted with uncanny or animalistic features when viewed from behind, however. They might have a cow’s tail, for example, and in some stories, they have a hollow or bark-covered back.
In some legends, huldras lure men into the woods for romantic encounters. If a child results, they might reappear to the father to present him with their unearthly child. In other stories, they steal human infants and replace them with their own babies
Sometimes, it seems, a huldra finds true love with a mortal, but the glamour or illusion that conceals her inhuman aspects is broken at her wedding, either when she enters the church or when the priest places his hand on her. At the same time, other stories state that, once married to a Christian man, the huldra will loose her tail but retain her beauty.
Huldras can be fiercly vindictive if they are mistreated or betrayed. They are sometimes depicted with superhuman strength.
Huldras are known by other terms as well. In Norway, she might be called a skogsfru or skovfrue, “lady (or mistress) of the forest.” She might also be called a skogsrå (“forest-guardian”) or Tallemaja (“pine-tree Mary”) in Sweden or, among the Sámi, Ulda. She is likely related to the Germanic myth of Holda, a protectress of agriculture and women’s crafts.
The male counterpart of a huldra is called a huldu or (in Norway) a huldrekarl. By all accounts, the males are often just as seductive—and dangerous—as the females.