A Crone or "the Old Hag" was a nightmare spirit in British and also Anglophone North American folklore which is essentially identical to the Anglo-Saxon mæra - a being with roots in ancient Germanic superstition, and closely related to the Scandinavian mara. According to folklore, the Crone sat on a sleeper's chest and sent nightmares to him or her. When the subject awoke, he or she would be unable to breathe or even move for a short period of time. Currently this state is called sleep paralysis, but in the old belief the subject had been hagridden.
In Irish and Scottish mythology Cailleach was a goddess concerned with creation, harvest, and the underworld. Moirae, particularly Atropos, are often depicted as hags.
In Persian folklore, Bakhtak (or Baxtak) has had somehow the same role as that of "the Old Hag" in British folklore. "It" sits on a sleeper's chest, awakening them and causing them to feel they are unable to breathe or even to move. Bakhtak also is used metaphorically to refer to "nightmare " in Modern Persian language.
Many stories about hags seem to have been used to frighten children into being good. Peg Powler, for example, was a river hag who lived in river trees and had skin the color of green scum. Parents told their children that, if they got too close to the water, she would pull them in with her extra long arms, drown them, and sometimes eat them. The parents hoped that the children would be afraid of the hag so they wouldn't go anywhere near the water. That way, they'd never fall in and drown. Peg Powler has other regional names, such as Jenny Greenteeth from Yorkshire and Nellie Longarms from several English counties.
Within Wiccan and other Neo-pagan communities the term crone refers to the elder aspect of the triple goddess (Maiden-Mother-Crone), or the older aspect of the Mother goddess]. It is also reserved for honored elder women. It is a term of respect, acknowledging the wisdom and strength that comes with age.
The expression Old Hag Attack refers to a hypnagogic state in which paralysis is present and, quite often, it is accompanied by terrifying hallucinations. When excessively recurrent, some consider them to be a disorder while many populations treat them as part of their culture as discussed in the sections dealing with the folkloric and mythologic interpretations.