“In Cory Finley’s razor-witted black comedy, Anya Taylor-Joy (The Witch) plays Lily, a chipper boarding-school student who rekindles her friendship with estranged childhood bestie Amanda (Olivia Cooke), mostly because the latter’s mother has paid her handsomely to do so. There’s something not quite right about Amanda. During the girls’ obligatory reunion, Amanda casually confesses that she feels no emotions about anything (and never has, really). She’s an intelligent, spookily self-aware sociopath, and Thoroughbreds’ wickedly funny opening stretch promises a twisted mismatched-buddy comedy about an uptight do-gooder under both social and financial obligation to tolerate the “off-putting” behavior of a “creepy” confidante from her past. But Thoroughbreds isn’t so easily pegged. It’s superbly unpredictable, moving fluidly into thriller territory and back again…. I think we have a future teenage-riot cult classic on our hands.” —A.A. Dowd, The A.V. Club. R. 92 Min.