In most religious traditions, there exists the conception that human beings can lose their freedom of will to an invading consciousness. We argue that possession myths emerge from evolved mental architecture and reflect a constellation of deep-seated beliefs about cognition, consciousness, and mind−body dualism. We also consider why possession is almost always considered frightening and aversive, thus explaining why the horror genre, and audiovisual horror in particular, has embraced the trope of possession. We analyze how possession works in 2 examples: The Exorcist (Blatty & Friedkin, 1973) and Supernatural (Kripke et al., 2005–2020). Finally, we conclude by briefly discussing the possibility that possession mythology represents an interesting test case for examining the origins of culture in general. Culture, as others have also suggested, exists first as an outgrowth of human psychological faculties but can then come to exert top-down causal influence on those same faculties.