Good zombie movies are metaphorical; Slither allegorizes living-dead horror as a critique of the American heartland’s boundless gluttony. The film’s aliens enter their victims through the mouth or stomach and compel people to consume endless quantities of meat—they grow so morbidly obese that they literally explode with extraterrestrial evil. Writer-director James Gunn, who wrote Tromeo & Juliet and the Dawn of the Dead remake, is obviously a fan of the genre, and he’s filled his movie with an encyclopedic onslaught of cinematic references: the town bar, for instance, is named Henenlotter’s after the director of 1982’s Basket Case, whose creature bears more than a passing resemblance to some of Slither‘s. The larger plot is a blend of Night of the Living Dead and Cronenberg’s version of The Fly: the decimation of a small town overrun by flesh-craving space slugs set against a love triangle among the aliens’ first victim, his wife, and the town sheriff (Michael Rooker, Elizabeth Banks, and Nathan Fillion, respectively). Gunn doesn’t reinvent the wheel but he does tighten its spokes a bit with some terrifying sequences and a witty, deadpan screenplay, and he leaves the audience hungry—for Slither 2.