Another carnival of cheap spooks and PG-13 thrills. This one revolves around the return to society of two rodential sisters after five years living with a deranged ghost-mom in a forest locale of variable remoteness. The eponymous Mama, a sort of Carrie/Dementor hybrid, follows her surrogate daughters to their new home and wreaks havoc upon disgruntled adoptive mother Annabel (Jessica Chastain), who undergoes — betwixt sweaty freakouts — a predictable change of heart. The supernatural premise is believe-it-or-not stomachable, if a variation on a recognizable theme — i.e. “unfinished business” — but debut director Andrés Muschietti seems afflicted with rather than energized by the burden to scare. He populates his film’s bulky middle with nonstop replicas of batshit encounters and only a passing interest in internal continuity thereamong. Here is Chastain, costumed in the style of Lizbeth Salander, shocked awake in the dead of night, tip toeing toward strange and haunting sounds! The film has one or two frankly touching moments, but its texture and imagery (to say nothing of its script) is by and large confused: inconsistent use of CGI, frequent modifications to Mama’s appearance and mode of attack, utter disavowal of medical terminology and metaphysical logic. A small-town library has a lost-and-found archive — “Aisle 17, every place has one!” — with the dimensions and industrial aspect of a military hangar, just to give you an idea. Forgettable performances by Game of Thrones’ Nikolaj Coster-Waldau as Chastain’s immediately comatose boyfriend; and the girls’ doctor, a poor man’s Tony Shalhoub, whose name I won’t even bother to look up. Still, it’d be no fun to deny that there’s a time and place for trash like this. What’s distressing about Mama is the suspicion that certain among the filmmakers may have taken it seriously.