Were it not for the abundance of full-frontal nudity and references to cheap pornography, David Robert Mitchell’s It Follows would be a slamdunk as an abstinence-only propaganda film whose core message is “screw around and malevolent demon spirit WILL track you down and kick your ass.” Mitchell, working from his own screenplay, takes the old movie trope of “death after teen sex” and gives it a fresh, though not totally coherent, spin. Maika Monroe (who reminds me of a slightly less winsome Catherine Deneuve circa Repulsion) stars as Jay, a young Detroit woman who gets bagged by a handsome though sketchy guy named Hugh (Jake Weary) who, post-coitus, ties her up and shows her the naked succubus who has been trailing him to tear him apart. But, now that he and Jay have done the nasty, Jay is “it” as in a game of tag, and the creeping soul sucker, which can change its appearance, will chase her. Peace out. The rest of the film is Jay running from a variety of slow-footed ghoulies with the help of her eager but utterly feckless sister (Lili Sepe) and friends Yara (Olivia Luccardi), who is reading Dostoevsky, and Paul (Keir Gilchrist), who wants to share Jay’s burden in the worst way. Though the movie features some solid shocks, it has a grim griminess about it, an air it comes about honestly, being set in Detroit. I’m not altogether a fan of this new chiller genre I call “the pointless animus of spirit beings.” I generally like my evil with a purpose and “sex is bad” doesn’t do it for me.