PG-13, 98 minutes. Waterford, Westbrook, Lisbon.

Things go bump in the night, and then some, in “The Boogeyman,” director Rob Savage’s well-played horror exercise that alternately goes from slow and brooding to loud and booming. It’s a movie that uses trauma as a catch-all, a perhaps too-convenient way to explain away the monsters underneath our beds or lurking behind open closet doors. But when it ratchets up the scares, it comes alive, and director Savage (“Host,” “Dashcam”) knows how to build out a sequence and ramp up its intensity. It’s a monster movie with bite. Chris Messina (“Air”) is Will Harper, a therapist whose wife was recently killed in a car accident. His daughters — high school-age Sadie (“Yellowjackets’” Sophie Thatcher) and elementary schooler Sawyer (Vivien Lyra Blair) — are dealing with the fallout in their own ways, mostly by retreating inward. There’s a supernatural force at play here, that of the Boogeyman, here rendered as a wall-crawling demon monster, seen mostly in shadows for a good portion of the film’s running time. Savage, working from a script based on Stephen King’s 1973 short story, spends time focusing on the Harpers and their family dynamics, so when weird things start happening to them, you care.