TL;DR: Other Mommy wastes a brilliant doppelgänger concept on recycled jump scares and chaotic editing. Arabella Olivia Clark impresses, Chastain commits, but the film is more exhausting than terrifying.

On paper, Other Mommy sounds like the kind of horror pitch that sells itself. Your mother has a double living somewhere in the house, it wears her face, it smiles her smile, and it is very much not your mother. Director Rob Savage, who gave us the pandemic-era Zoom chiller Host and later The Boogeyman, adapts Josh Malerman’s novel Incidents Around the House, and the Universal release arrives after a summer of its trailer playing before seemingly every multiplex screening. With Jessica Chastain in the dual role of Ursula and her uncanny copy, this should have been an easy win. Instead, Other Mommy is a 94-minute fever spike that never breaks, and it ranks among the most frustrating studio horror releases I’ve sat through this year.

The setup is lean. Young Bela (Arabella Olivia Clark) already knows the creature lurking in her bedroom, a thing that takes the shape of her mother. Her father Russell (Jay Duplass) soon sees it too, and from that moment the family simply accepts that a hostile replica of Ursula is roaming their home. I can admire a horror film that skips the tired “nobody believes the kid” routine, but skipping it only works if you replace it with something. Here, nothing fills that gap, and the movie starts at a pitch most films save for their final act.

Jessica Chastain goes big while the scares stay small

Chastain commits completely, and I respect that. As the real Ursula she leans into heightened melodrama, and as the Other Mommy she flashes a wide grin that should chill your blood but lands closer to silly. Smile proved a fixed grin can be terrifying when the film builds dread around it, while Us showed how effective a doppelgänger becomes when it carries real menace and meaning. Chastain’s creature has neither. It plays pranks rather than hunting anyone, which makes it difficult to fear even when the film insists we should.

The scare design is the bigger problem. Most frights follow one pattern: the camera circles a character who has no idea what’s behind them, then reveals the Other Mommy waiting there. It works once, maybe twice, then it becomes as predictable as a scripted jump scare in a horror game you’ve already replayed three times. Ball pits, gravity that suddenly misbehaves and a CGI Chastain who melts or flails wildly all cycle through, but every moment carries the same weight, whether it’s a real threat or a fake-out. When everything is a shock, nothing shocks, and the film never shows it understands that.

Arabella Olivia Clark deserves a much better movie

The real discovery is Clark, who carries the emotional burden with a natural, grounded presence that feels truer than anything around her. She plays younger and more wide-eyed than her actual age, and for much of the film she is the only person reacting like a human being stuck in a nightmare. Even when Bela is flung around during an anniversary gathering at the house, the adults barely seem rattled, which leaves Clark doing the heavy lifting of making any of this feel dangerous. Over time, though, even her performance seems to sag under the weight of a premise that keeps repeating itself. I can’t blame her, because the script gives her very little room to grow.

Duplass, meanwhile, appears to have wandered in from an entirely different genre. His easygoing, slightly bewildered energy works well in indie comedies, but here it turns Russell into something closer to a sketch character than a frightened father. With Chastain in melodrama mode, Clark playing it naturalistically and Duplass reading as broad comedy, the three leads never feel like a single family. That disconnect matters enormously in a story built entirely on a household being invaded from within.

The story buried beneath the noise

There’s a genuinely compelling idea hiding inside Other Mommy. Bela suspects her mother is having an affair, which means the horror of a false Ursula could have served as a sharp metaphor for a child realising a parent isn’t who she seems. That is fertile ground, the territory The Babadook and Hereditary mined so effectively by turning family fractures into something monstrous. Even Coraline‘s button-eyed Other Mother, the obvious spiritual ancestor here, worked because the fantasy and the fear were tied to what the child wanted and lacked at home.

Unfortunately, the movie loses that thread almost as soon as it finds it. The creature drifts from maternal deception into impersonating other people, and the “Mommy” core of the concept fades into the background. That shift may come from the source novel, but the film never builds a visual or emotional framework that makes it feel intentional. Instead of digging deeper into a family secret, it settles for a stream of tricks that grow more interchangeable as the runtime drags on.

Editing that feels like it was done with a chainsaw

The pacing is where Other Mommy truly falls apart. Scenes start and stop with little sense of rhythm, as though entire stretches were removed late in the process, and the opening feels like it begins halfway into the story. There’s barely any build, barely any breathing room and almost no sense of physical geography inside the house. Horror relies heavily on spatial awareness, knowing where the dark corner is and how far the character is from it, yet the film rarely establishes it. Without that grounding, the scares built on negative space lose their power before they arrive.

The result feels like a horror film that panicked about losing its audience’s attention and responded by never letting the tension settle. Some viewers may read the chaos as a deliberate attempt to capture a child’s nightmare logic, and that interpretation is fair on paper. The issue is that even nightmares need a shape, a mounting sense of dread or a recurring image that sticks. Other Mommy offers plenty of frantic activity, but far too little of it lingers once it ends.

Verdict

Other Mommy has a strong premise, a fully committed Jessica Chastain and a standout turn from Arabella Olivia Clark, but it squanders them with repetitive jump scares, mismatched performances and editing that strips away rhythm and tension. The affair subplot hints at a smarter, more personal horror film that never materialises, and the creature is too playful to be properly frightening. Horror completists and devoted Chastain fans may find some curiosity value here, especially anyone who enjoys watching an actor go all in. Everyone else should revisit Us, Hereditary or Savage’s own Host instead.