The Nocnitsa in Slavic mythology, is a nightmare spirit that also goes by the name kriksy, plaksy, plachky, plaksivicy, kriksy-varaksy, kriksy-plaksy, night maiden. She is referred to as Nocnica or Płaczka in Polish, горска майка (gorska majka), ношно (nošno) in Bulgarian, Шумска маjка (Šumska majka), бабице (babice), ноћнице (noćnice) in Serbian, mrake, vidine in Croatian, nočnine, mračnine in Slovene.
The Nocnitsa is also present in Russian and Slovakian folklore. She is known to torment children at night, and a stone with a hole in the center is said to be a protection from the Nocnitsa. Mothers in some regions will place a knife in their children’s cradles or draw a circle around the cradles with a knife for protection. This is possibly based on the belief that supernatural beings cannot touch iron.
The Nocnitsa is known to sit on one’s chest, drawing «life energy». Because of this, many refer to Nocnitsa as a type of vampire. The Nocnitsa will often continue visiting. According to some folklore, night hags visit when one sleeps on one’s back, with the hands on the chest (a position allegedly called «sleeping with the dead»). According to some folklore, night hags are made of shadow. She might also have a horrible screeching voice. She might allegedly also smell of the moss and dirt from her forest of origin.
The Nocnitsa is almost certainly linked to the common apparition seen during the hypnagogic state of sleep.