This article examines nightmare narratives collected as part of a person-centered ethnographic study of altered states of consciousness (ASCs) and supernaturalism in a mainland Puerto Rican community in the late 1990s. Utilizing a descriptive backdrop informed by cross-cultural studies of ASCs and highlighting the relevance of recent insights from the cognitive sciences of religion and from the anthropology of embodiment or cultural phenomenology, I examine the lived experience and psychocultural elaboration of diverse Puerto Rican nightmare events. Taking the nightmare to be a trauma in its waking-nightmare sense (i.e., through the extreme fright caused by sleep paralysis) as well as an intrusive, traumatic memory in its posttraumatic sense (i.e., a reliving of trauma themes in dreams), I show how the perceptual and interpretive processes evoked by intensely affective ASCs both inform and are informed by Puerto Rican religious and spiritualistic orientations and values.