"Jesus Christ, is that Michael Shannon?" I blurted out recently while watching Groundhog Day (1993)—specifically the scene in which Bill Murray delights a young husband and wife by giving them tickets to Wrestlemania. The bit part marked Shannon's big-screen debut, and since then he's appeared in more than 40 films, emerging as one of the most impressive young movie actors to come out of Chicago theater. Shannon scored an Oscar nomination playing John Givings, the mercilessly sarcastic mental patient in Revolutionary Road (2008), and ran away with The Runaways (2010) playing silky-smooth rock Svengali Kim Fowley. Last year he proved he could carry a film all by himself as the molar-grinding family man convinced the end of the world is nigh in Take Shelter (2011). Even the protagonist can't be sure whether he's a mystic or a madman, but in Shannon's wrenching performance he seems almost physically torn apart by a future only he can perceive.