Other Mommy Review: Rob Savage's Doppelgänger Horror

The film centers on young Bela (Arabella Olivia Clark), a girl navigating the awkward, tender years of childhood in a home that feels just a little too quiet. Her mother, Ursula (Jessica Chastain), is present but distant, a woman seemingly drained by the demands of motherhood. Then the Other Mommy appears - a sinister entity that looks uncannily like Ursula, but with a predatory gleam in her eye and a far more permissive attitude toward Bela's desires.

At first, the entity is a secret friend. But as the runtime progresses, the relationship between Bela and the Other Mommy transforms from a playful fantasy into a terrifying codependency. The film follows Bela as she is drawn into this entity's dark world, forcing her father Russ (Jay Duplass) and the extended family - including a brief but effective turn from Karen Allen as Grandma Ruth - to confront the possibility that the monster in the house is wearing their own face.

Rob Savage has always had a knack for atmosphere. He understands that the scariest things often happen in the corner of the frame, just out of focus. In Other Mommy, he uses this skill to great effect early on. The cinematography is cold and clinical, turning a standard suburban home into a sterile playground for psychological warfare. The sound design is aggressive, utilizing silence to create a vacuum that the audience knows will eventually be filled with a scream.

However, the film's greatest asset is Jessica Chastain. She delivers a dual performance that is both heartbreaking and horrifying. As Ursula, she is exhausted, loving, and frayed at the edges. As the Other Mommy, she flips a switch. She doesn't just play a monster; she plays a better mother. The Other Mommy is fun, she says yes to everything, and she treats Bela like an equal. Watching Chastain navigate this duality is the primary reason to buy a ticket. She brings a physicality to the role of the entity - a predatory stillness that mirrored the creaky floorboards of the house.

The young Arabella Olivia Clark holds her own against this heavyweight presence, though the script often asks her to carry burdens that require the emotional nuance of an adult. Jay Duplass is serviceable as the skeptical father, though his role is largely reactive, serving as the anchor to reality that the plot inevitably pulls away.

Where Other Mommy falters is in its screenplay. The first hour establishes a masterclass in suspense, but as the dark world expands, the film loses its grip on logic. It attempts to build a mythology around the entity - rules, lore, and cycles - but these elements feel half-baked and distract from the more compelling emotional core of the story: the guilt of a mother who feels she isn't good enough and the fantasy of a child who wants a parent without flaws.

By the time the climax arrives, the film has traded psychological terror for standard horror fare. The ambiguity that made the first act so chilling is replaced by exposition dumps and chaotic set pieces. It becomes less a story about a fractured family and more a generic siege film, losing the very identity that made it interesting. The rating of 5.5/10 on TMDb reflects this disparity; audiences are clearly reacting to the wasted potential and a third act that collapses under the weight of its own ambition.

Pros

• Jessica Chastain's performance: She is magnetic, terrifying, and deeply sad in equal measure.
• Atmosphere: Rob Savage knows how to build tension with light, shadow, and sound.
• The premise: The idea of a child preferring a monstrous doppelgänger to their real parent is rich thematic ground.
• Runtime: At a tight 93 minutes, the film never overstays its welcome, though it could have used a few more minutes of character development.

Cons

• Convoluted lore: The rules of the entity are muddled and inconsistent.
• Third-act collapse: The film pivots from psychological horror to generic jump-scare territory.
• Underutilized cast: Dichen Lachman, Arian Moayed, and Karen Allen are given very little to do.
• Pacing: The middle section drags significantly as Bela explores the "other" world.

Other Mommy is a frustrating experience. It features one of the best performances of Jessica Chastain's horror career and some genuinely effective direction from Rob Savage, but it ultimately gets in its own way. The film is at its best when it is a quiet, domestic drama about a family falling apart, and at its worst when it tries to be a supernatural blockbuster.

If you are a fan of Chastain or Savage's previous work, it is worth a watch, if only to witness the sheer commitment of the lead performance. However, audiences hoping for a tight, terrifying thriller might find themselves frustrated by a film that looks the part - but lacks the substance to truly haunt your dreams. In the end, Other Mommy is a film that, like its titular monster, is trying desperately to be something it isn't.