There are a few things to be feared when a fog rolls into a New England town in The Mist—monsters, for one. But as a group that gets trapped in the local supermarket quickly discovers, the neighbors aren’t exactly nurturing bosoms of warmth, either. Those who haven’t read the Stephen King novella upon which writer-director Frank Darabont’s script is based are surely curious about what exactly is the source of the horror lurking in the fog (and no, this is not a rip-off of The Fog) that envelops the rural area after a violent electrical storm. It’s scary stuff—bug-, slime-, and blood-phobes, you’re going to squirm—but often it’s not nearly as brutal as the humanity that tries to contain it. And therein lies King’s triumph as a horror writer who emphasizes earthly characters—in this case, most notably a dad and young son (Thomas Jane and Nathan Gamble), a religious zealot (a fierce, frightening Marcia Gay Harden), and a young teacher (Laurie Holden) who believes—heh—in the goodness of people instead of supernatural ones, a shrewdness that ultimately elevates The Mist into the tense, wrenching, watchable film that it is. Darabont, who also crafted big-screen adaptations of King’s writings for The Green Mile and The Shawshank Redemption, deserves a big credit, too: For one, monster movies aren’t exactly in vogue, considering that a cheesy-looking tentacle, pterodactyl, or giant spider (and all three make appearances here) generally send modern audiences laughing out of the theater. These otherworldly creatures look pretty good—weird and repellent, and they attack with such ferocity and speed (though not what-the-hell-just-happened speed) that you’ll be putting a vice grip on your popcorn bag before you have the chance to scoff. Darabont also elaborated on King’s ambiguous ending. King himself called the new twist “shocking”; I’d add devastating, though it’s undoubtedly going to be a love-it-or-hate-it thing. The ending reinforces the strength of The Mist, which meshes its killer-beasts concept with a Lord of the Flies-like dissolution among their waiting victims. The bugs are sickening, but the bile underneath the townsfolks’ surface friendliness will turn your stomach as well.