Once bitten, the victims of a werewolf attack don't morph into lycanthropes right away, but undergo a gradual transformation which they can only watch in horror, as their bodies betray them. Hair starts appearing where it wasn't before, their frames bend into unfamiliar shapes, and they develop powerful appetites for things they would normally find repulsive. In other words, becoming a werewolf is not unlike being an adolescent girl, a notion that serves as the clever conceit behind Ginger Snaps, a smart, resourceful, and wickedly funny teen-horror film that reinvents the werewolf myth as a potent metaphor for pubescent angst and humiliation. Working from a lively, unsparing script by Karen Walton, Canadian director John Fawcett touches on the same unsettling feelings evoked by Carrie, which was also fueled by the intense mortification that goes along with the first signs of womanhood. Both films are triggered by a late-blooming high-school outcast getting her first period, though the girl in Ginger Snaps is at least spared the trauma of getting pelted with tampons. Two or three years late to menstruation, Emily Perkins and Katharine Isabelle are virtually inseparable sisters whose shared dark sensibility alienates them from their peers; their idea of fun is taking Polaroids of their own bloody mock-suicides. One night, they decide to exact revenge on one of their school's "popular" girls by faking the grisly death of her dog. But the plan goes awry when Isabelle, shortly after having her first period, is savagely mauled by a wild animal in the forest. Her wounds heal almost instantly, but the scars sprout tufts of hair, and she's overcome by a new, insatiable lust for boys and blood. Alarmed by the sight of her sister turning into a monster—and perhaps a little jealous because Isabelle is growing up first—Perkins enlists the help of Kris Lemche, a local pot dealer and amateur botanist, to find a cure for Isabelle's infection. On a limited budget, Fawcett gets around the cheapo effects with old-fashioned editing tricks and buckets of gore, but he mostly relies on what money can't buy, like inspired dialogue and superb lead performances. Outside of being a taut and effective genre film, Ginger Snaps isn't afraid to delve into the dark, uncomfortable corners of adolescence, and it's remarkably perceptive about the true horrors of becoming an adult. For all their gruesome confrontations with werewolves, the sisters are never more frightened than when their oblivious mother (played by a scene-stealing Mimi Rogers) tells them about "what guys really want." A cult item in the making, Ginger Snaps falls prey to a conventionally bloody finish, but it's far better to run out of ideas than to not have any at all.