The lidérc is a singular supernatural being of Hungarian folklore, with three varieties that borrow traits from one another. The oldest form is a “miracle chicken” that hatches from the first egg of a black hen kept warm under a person’s arm. It attaches itself as a lover, sits on the body and sucks blood until its host grows weak and sick — the source of the Hungarian word for nightmare, lidércnyomás, “lidérc pressure.”
The second is a tiny earthly devil, and the third is a Satanic lover that flies at night as a light, a will-o’-the-wisp or a bird of fire. It enters through chimneys or keyholes, is impossible to outrun, and must vanish at the first crow of the rooster at dawn. A being that clings to the sleeper and gnaws them away by degrees meets our world’s concern with sealed lack.