There's no rational way of negotiating with Bug, and you get the sense that director William Friedkin likes it that way. The perfect thriller for the era of truthiness, it tight-focuses on Agnes (Ashley Judd), a spiritually dissolute waitress, and Peter (Michael Shannon), a mild if odd war vet. The two hook up in a motel room that suggests Dante by way of Godot. Peter's interest in conspiracy theories explodes into a mounting obsession with defeating a "bug" contracted in a Middle East conflict. Agnes--haunted by a tragedy that, like everything else here, may or may not be real--is glad for the oblivion his madness offers: microscopes, aluminum-foiled walls, and sliced flesh play prominently in their mounting delusions. Written by Tracy Letts, on whose off-Broadway hit it's based, Bug is astringently minimalist in technique, occasionally unbearably gruesome, and eventually so over-the-top that you don't know whether to laugh or despair over the human condition, although both are apt. Shannon, best known as the creepy über-Christian in World Trade Center, brilliantly chews his way through Lett's hyperdelusional tirades, but it's Judd's balls-out portrayal of naked human neediness that sticks in your craw after the last tooth has been extracted (don't ask). There are no answers here, just a widening whole where souls should be and then blackness.