The author reviews myths and traditional tales in which the protagonist is a filicidal mother. In a displaced form, filicidal mothers appear as the ubiquitous witches of folklore. This imago is universal in fantasies and pavor nocturnus in children, regardless of the quality of care of the real maternal figures. To this phenomenon—the result of defensive externalization of primitive fears—a fundamental dimension is added when this dread seems corroborated by the mother's manifestly murderous wishes and behavior. Clinical examples of this pathogenic circumstance are provided, with comments on the development of dissociation versus repression, depending on the severity of early traumas. The evolution of symptoms and character disorder in adulthood is discussed, as well as interpretive and technical dilemmas posed by these patients.