There's a so-spooky-it's-funny moment in Mama that demonstrates how a relatively simple and derivative horror film, if executed well enough, can give you a few goose bumps of fear. Annabel and Lucas (Jessica Chastain and Nikolaj Coster-Waldau), a punky but nice bohemian couple, have taken over the care of their two nieces 8-year-old Victoria (Megan Charpentier) and 6-year-old Lilly (Isabelle Nélisse), who were found in a cabin in the woods five years after being kidnapped and abandoned by their crazy, violent financier father. (He went ballistic during the U.S. economic meltdown, then killed himself.) The two emerged from their ordeal as wild, feral children, but that's not what's scary. It's the fact that they found a spiritual ''guardian'' named Mama. We assume that she's some sort of ghost, and therefore not all that, you know ... corporeal. But then the director, Andy Muschietti, frames a terrific shot just outside the girls' suburban bedroom: We're peering through the doorway, watching one of them play with a lavender sweater that's being tugged upward by something very tall, though we can't see what. Instead, we hear ominous clucks on the soundtrack. It's an elegant, shuddery tease, like a J-horror moment staged by the young Steven Spielberg.
Mama lifts almost every one of its fear-factor visuals from earlier films: the rotting black passageways that spread like mold over the walls (very Ringu meets Repulsion); the crouched figures that skitter and pounce à la the infamous ''spider'' outtake from the original Exorcist; the way that Mama, with her arms like smoky-shadowy bent tendrils, evokes both the monster from the Alien films and also, in a funny way, the crumpled-puppet gothic mischievousness of Tim Burton animation. Nothing in the movie is quite original, yet Muschietti, expanding his original short (see box), knows how to stage a rip-off with frightening verve. It helps to have an actress on hand as soulful as Jessica Chastain, who, with her severe black-bang haircut, suggests Liv Ullmann playing Joan Jett. The reason her performance matters is that even though Mama is just a megaplex horror bash that keeps goosing you with shrieky blasts on the soundtrack, its true subject is motherly love. The picture links Annabel's protective ardor with the very monster she's trying to protect the children from. In doing so, it finally does something that's a little bit original: It invites you to care about what's scaring you. B