Purpose:To test the hypothesis that supernatural agents (SAs) appear in nightmares and dreams in association with evidence of diminished agency within the dreamer/dream ego.Methods:Content analyses of 120 nightmares and 71 unpleasant control dream narratives.Results:We found that SAs overtly occur in about one quarter of unpleasant dreams and about half of nightmares. When SAs appear in a dream or nightmare they are reliably associated with diminished agency in the dreamer. Diminished agency within the dreamer occurs in over 90% of dreams (whether (...) nightmares or unpleasant dreams) that have overt SAs. In about half of nightmare reports the SA appears suddenly with no clear emergence pattern. In some two thirds of unpleasant dreams, however, the SA emerged from a human character. The SA’s gender was indeterminate in most dreams with SAs but the SA communicated with the dreamer in 24% of nightmares and only 13% of unpleasant dreams. In most nightmares, the SA intended to harm the dreamer and in one third of nightmares the dreamer was the victim of physical agression by the SA. SA intentions in unpleasant dreams were more varied and actually benign in 13% of cases.Conclusion:Supernatural agents reliably appear in nightmares and unpleasant dreams in association with diminished agency in the dreamer. Diminished agency in an individual may facilitate supernatural agent cognitions. (shrink)