Here's one creepy love story: Agnes (Ashley Judd), a hard-up woman, meets Peter (Michael Shannon), a weirdo man. The two hole up in Agnes' shabby motel-room home on the edge of desert-nowhere Palookaville, where, when not doing waitress duty at a lesbian bar, she spends her time fearing her recently paroled ex-husband, Jerry (Harry Connick Jr.). And somewhere between sex and a dark night of the soul, Peter passes his paranoid convictions about government surveillance, secret mind-control experiments, and the invisible insects he says are burrowing into his skin along to Agnes, who desperately needs something in which to believe. Whatever has bitten Peter, causing him to claw at his own skin, spreads to the woman beside him, too. In time their motel haven becomes one twisted bug hole, which they seal off against the light of day. Woe, let's just say, to anyone who shows up at the door.
Bug, written by Tracy Letts, was originally an intimate, unsettling play in which the confines of the stage could reflect the emotional and psychological claustrophobia of the subject matter. Letts adapted his own script, but the movie is now also inflected with the stylistic details of director William Friedkin, who clearly took on the project with the aesthetic affinity of one who made the creepy and claustrophobic memorably manifest in The Exorcist. Here, the filmmaker has to expand the contours of the play's static physical dimensions a challenge that Friedkin meets with about as much success as possible for an edgy drama so essentially...playlike. The enjoyably icky heart of Bug is still contained within the airless, increasingly ''bug-proofed'' room that becomes Agnes and Peter's whole world. But the director also emphasizes the camera's ability to heighten our sense of dislocation, first by opening with a larger, lonelier desert landscape, and then by prowling restlessly around the tormented protagonists in what amounts to the visual equivalent of what an itch feels like.
Shannon, a compelling stage actor with a mean-baby face that morphs by imperceptible degrees from innocent to madman, originated the role on the stage. And it's difficult to imagine anyone else playing the part, so authoritative is his access to every twitch of Peter's growing mania. But that doesn't mean another filmmaker might not have jettisoned him for a more famous screen presence, and it's to Bug's benefit that Shannon is given free rein to set the pace of the drama's queasy tension.
Then again, as screen-friendly casting goes, Judd is an exciting match; it's rewarding to see her find not only what's tough (she's always good at that) but also what's bruised, soft, and responsive in such a mutable character. Her face stripped bare, Judd is capable of great, bone-weary stillness, and her depiction of unraveling, in symbiotic identification with the new, dangerous man in Agnes' life, is an unexpected pleasure. B+