Critics have universally praised Charlize Theron's performance in Monster, and the praise, for once, is astonishingly deserved. The gorgeous star of The Italian Job and The Cider House Rules vanishes into the character of Aileen Wuornos, a real-life serial killer and prostitute who murdered at least seven men in Florida. Monster traces her relationship with a young woman named Selby (Christina Ricci, The Ice Storm, Buffalo 66), which intertwines with Wuornos's murder spree. This remarkable movie finds compassion for Wuornos but unflinchingly faces her brutal crimes; Theron expresses this woman's horrific life history without softening her terrifying, dead-eyed stare. This is a gripping, devastating performance, a physical and psychological transformation comparable to Robert DeNiro's in Raging Bull. The movie's moral and emotional complexity wouldn't succeed without this searing performance--but succeed it does, and it will stick with you for some time afterward. --Bret Fetzer