1. Horror films literally scare the hell out of us. They frighten us away from any dangerously unorthodox religious or anti-religious leanings, shepherding us back to the religious mainstream. This religious function is especially prevalent in the sub-genre of evangelical Christian horror movies, like the church basement blockbuster A Thief in the Night (1973), a low-budget, low-fi cinematic nightmare in which the heroine, Patty, is left behind by her friends, her newly born-again husband, and God in a world of zombie-like thugs dead-set on forcing her to take the Mark of the Beast, a binary computer readout of the number 666. (Oddly enough, in the more recent Left Behind series, Thief's sense of the horror of being left behind in a post-rapture world after God is replaced by a sense of adventure, as the righteous remnant does battle against the diabolical powers that be. You have to feel bad for the raptured ones, who are missing out on all the action.)
2. Horror films can be myths that sanctify order against chaos. So common is this kind of myth that religion scholars have a name for it: the Chaoskampf, or "chaos battle," in which social and cosmological order is established by facing and overcoming monstrous forces of chaos. In the Babylonian creation epic Enuma Elish, for example, Marduk creates world order, with Babylon as its center, by slaying his turbulent chaos goddess mother Tiamat. And in the biblical book of Revelation, God and Christ must defeat the monstrous Red Dragon "who is the devil" and his beasts in order redeem and renew the world and its capitol, the holy city of Jerusalem.
Horror films often serve a similar function, as mythic battles of blessed order against diabolical chaos. Most often, these forces of chaos are personified in terms of racial, ethnic, sexual, and religious otherness, projected as monstrous threats to "our" familiar sense of order. In the course of the film, viewers reenact the myth, facing our monsters—which seem to be winning for a horrifically long time—and ultimately defeating them. In the process, "we" are ritually purging ourselves of otherness, reestablishing and blessing the established social order (e.g., white Christian American patriarchal heteronormativity). Such films put a face on otherwise vague uneasinesses and unnamable insecurities, to slay them, and to send them back to hell where they belong, returning us to a sense of security and safety.
3. Horror films host otherwise unwelcome religious questions. Monsters are always asking questions that Sunday School teachers are loath to entertain. Dracula and his many undead descendants invite us to ask, “Is eternal life really desirable?” Zombies can't help but make us wonder, “Is the resurrection of the dead really something to look forward to?” And Frankenstein's monster, Blade Runner's replicants, and Westworld's hosts all press the question, “Who is the real monster—the creature or its creator?” Horror films offer spaces to ask deeply religious questions that are not always welcome from the pews.
4. Horror films lean into the scary side of holiness. Some argue that religion, at its core, is a response to an encounter with an unknowable, radical otherness that is both fascinating and terrifying, in the face of which our own sense of selfhood and control is lost—what we might call ego annihilation before the wholly other. Mystical religious experience is often described in this way. So also is the experience of fascination and terror in the face of the monstrous otherness in many supernatural horror films. Such films testify to the chaotic, ungrounding, indeed monstrous dimensions of the holy, which is not reducible to our modern Enlightenment identification of it with goodness, beauty, and human thriving.
What might these four religious dimensions of horror reveal about religion? To be sure, religion is often about maintaining, even ordaining, our all-to-human constructs of social and cosmological order, sanctifying normative identities and behaviors while demonizing others. But religion is also about opening toward that which can subvert and unground those constructs, exposing us to radical unknowing and opening us to otherness. The horror.