In European
folklore and folk-belief of the
Medieval and
Early Modern periods,
familiar spirits (sometimes referred to simply as "
familiars" or "
animal guides") were believed to be supernatural entities that would assist
witches and
cunning folk in their practice of
magic. According to the records of the time, they would appear in numerous guises, often as an animal, but also at times as a human or humanoid figure, and were described as "clearly defined, three-dimensional… forms, vivid with colour and animated with movement and sound" by those alleging to have come into contact with them, unlike later descriptions of
ghosts with their "smoky, undefined form[s]".