'Bug" is a different kind of woman-in-peril movie starring Ashley Judd, which has long been its own specific genre.

'Bug" is a different kind of woman-in-peril movie starring Ashley Judd, which has long been its own specific genre.

Judd is indeed in peril here once again, following "Kiss the Girls" and "Twisted" and the like, but she gets to prove she can actually act with some depth, and not just look pretty under strain. Whatever unexpected ability she shows in the early scenes of this paranoid thriller go utterly to waste, however, as the film spirals ridiculously out of control by the end.

The film comes from veteran William Friedkin ("The Exorcist," "The French Connection"), a director who has seen better days, decades ago. Friedkin still maintains a mastery of suspense for the first half or so — though he does rely a bit too heavily on that "Apocalypse Now"-style, ceiling-fan-as-helicopter effect — and "Bug" can be intriguing as a character study of two damaged people who find a whole new way to damage each other further. Until it just becomes silly, that is.

Judd stars as Agnes, a lonely waitress at a run-down bar who lives in an even rattier motel, subsisting on a diet of cigarettes, vodka and pot. Agnes' only friend is fellow waitress R.C. (Lynn Collins), who is pretty and gay and who flirts with her and makes her feel loved, or at least vaguely wanted. Sporadically, Agnes' brutish ex-husband (Harry Connick Jr. as a believable bad guy) breezes in and abuses her physically and mentally.

Agnes' pathetic life gets shaken up by a quiet drifter named Peter (Michael Shannon, whose presence and delivery are riveting). Peter hangs out at the bar one night and quickly moves in with Agnes. He's decent to her, which most people aren't; she listens to him, which most people don't. Their shared neediness is palpable. Their big love scene, however, is laughable.

Once Agnes and Peter fall for each other, it doesn't take long for him to suck her into his delusional conspiracy theories involving the military, scientific testing, chemical technology and ... bugs! Hence the title.

The movie is based on the play by Tracy Letts (who also wrote the script), and it feels like it. Much of the action takes place in Agnes' room, which slowly evolves — or rather, devolves — as the couple's fear and co-dependency grow.

If the idea of the bugs had remained as a metaphor, one that's open for interpretation, we would have been fine. But then a doctor (Brian F. O'Byrne) shows up at the door, along with a mysterious pizza that no one ordered. Eventually the room is covered in aluminum foil and insect-zapping strips, and "Bug" ends shrilly, overzealously, explosively. It's sound and fury signifying nothing, though it was probably intended to be profound.