You know something is up when what looks like a cheapie fright flick is produced by Guillermo Del Toro (Pan’s Labyrinth) and boasts an Oscar-nominated actress in Jessica Chastain (Zero Dark Thirty). Mama doesn’t live up to their potential, but the film knows how to creep you out. Two sisters, Victoria (Megan Charpentier) and Lilly (Isabelle Nélisse), considered dead for five years, are found in the wilderness. The feral girls are taken in by their uncle Lucas (Game of Thrones’ Nikolaj Coster-Waldau) and his raven-haired girlfriend, Annabel (Chastain), who try to solve the mystery of how they survived and why they still seem to be haunted by a menacing ghost they call “Mama.” Time now for me to shut up. To get a taste of the film’s eerie essence, check out the acclaimed short of the same title (it’s on YouTube) that director Andrés Muschietti and his producer sister, Barbara, crafted in 2008. The feature-length Mama – which Neil Cross (Luther) wrote with the Muschiettis – can’t hide its stretch marks. But Chastain digs deep, going beyond the call of scream-queen duty to find the passion that gives horror a pulse.