**"Other Mommy,"** the Blumhouse/Atomic Monster supernatural horror film directed by Rob Savage and starring Jessica Chastain in a dual role, opens in theaters October 9, 2026, with no reviews yet on Rotten Tomatoes. Trader sentiment reflects expectations shaped by the strong horror pedigree—James Wan producing, Savage’s prior genre work like *Host* and *The Boogeyman*, and the adaptation of Josh Malerman’s 2024 bestseller *Incidents Around the House*. Multiple trailers, including a September second trailer that quickly amassed millions of views, have driven visibility and pre-release buzz ahead of the wide release. Historical performance of similar mid-budget Blumhouse titles and critical response to Chastain’s recent genre turns provide the main benchmarks, while the October timing positions it for Halloween-season attention. Early critic screenings and opening-weekend reviews will quickly determine whether the Tomatometer settles in the mid-50s range or higher once scores aggregate.