Jessica Chastain's 'Other Mommy' Set to Dominate Box Office With Biggest Horror Book Opening Since 'It: Chapter Two'

Jessica Chastain returns to the horror genre this weekend with "Other Mommy," a supernatural thriller that industry forecasters predict will open to $20-29 million domestically—on track to become the highest-grossing horror book adaptation debut since "It: Chapter Two" raked in $91 million during its 2019 opening weekend.

Universal Pictures and Blumhouse's October 9 wide release puts Chastain in dual roles as both a loving mother and the sinister entity that slowly replaces her. Directed by Rob Savage and based on Josh Malerman's 2024 novel "Incidents Around the House," the film follows a family terrorized by a doppelganger that takes over their home—and their lives.

Early tracking suggests "Other Mommy" could mark another win for the horror genre, which has been one of 2026's most reliable box office success stories. The film's timing places it in the heart of October, traditionally the strongest month for scary movies as audiences seek Halloween season thrills.

Chastain's Return to Horror

For Chastain, "Other Mommy" represents a return to familiar territory. The Oscar-winning actress has delivered memorable performances in horror and genre films including "Mama" (2013), Guillermo del Toro's "Crimson Peak" (2015), and "It: Chapter Two" (2019), where she played the adult Beverly Marsh.

The film showcases Chastain's range as she portrays a suburban mother dealing with everyday family challenges while simultaneously embodying the unhinged, body-twisting creature that infiltrates her home. Trailers released in September highlighted unsettling scenes of the doppelganger mimicking human behavior while revealing its sinister nature through subtle physical distortions.

Savage, known for his 2020 found-footage horror hit "Host," brings his signature tension-building style to Malerman's source material. Nathan Elston adapted the screenplay from Malerman's novel, which received critical acclaim for its slow-burn psychological terror and unreliable narrator structure.

The Josh Malerman Connection

Josh Malerman, author of the bestseller "Bird Box" that became a Netflix phenomenon in 2018, has established himself as one of contemporary horror's most adaptable voices. "Incidents Around the House," published in 2024, marked a departure from "Bird Box's" sensory deprivation premise toward a more intimate, home-invasion nightmare.

The novel centers on eight-year-old Bela, who begins noticing that something is wrong with her mother. Small behavioral changes escalate into full-blown terror as Bela realizes the woman living in her house may not be her mother at all—or at least not anymore. The first-person narration from a child's perspective makes the horror feel immediate and visceral, as Bela struggles to convince adults that danger lurks within their own home.

Malerman's work has proven remarkably cinema-friendly. Beyond "Bird Box's" massive streaming success, adaptations of his novels "Unbury Carol" and "A House at the Bottom of a Lake" are in various stages of development. His ability to craft high-concept horror premises that translate to visual storytelling has made him a hot property in Hollywood.

Horror's Banner Year Continues

If "Other Mommy" hits the upper end of its $20-29 million projection range, it will cement 2026 as one of horror's strongest years at the domestic box office. Earlier hits including "The Silencing Spiral" ($47 million opening), "Last Rites for Emily" ($83 million total), and "Night Swim's" surprise $54 million finish demonstrated that audiences remain hungry for well-crafted scares.

The genre's success has attracted A-list talent who once avoided horror projects. Chastain joins Scarlett Johansson, Oscar Isaac, and Margot Robbie as major stars headlining horror films in 2026, a far cry from the days when genre work was considered a career risk for prestige actors.

Universal originally dated "Other Mommy" for a May 8 release before moving it to October 9, placing it strategically in the Halloween corridor. The shift likely benefited the film—horror performs strongest in October and January, when audiences actively seek out scary content.

Competition and Box Office Context

This weekend's other major release, "The Social Reckoning"—Aaron Sorkin's follow-up to "The Social Network" focusing on Facebook's recent controversies—is projected to underperform with a disappointing $8 million opening despite starring Jeremy Strong fresh off his Emmy-winning "Succession" run.

The contrast between the two films illustrates a fundamental shift in theatrical moviegoing. Prestige dramas struggle to find audiences who increasingly wait for streaming availability, while high-concept horror and action films continue drawing crowds to theaters. "Other Mommy" benefits from being the kind of communal experience—jump scares, audience reactions—that loses something when watched alone at home.

Industry analysts note that "Other Mommy's" tracking numbers surpass those of recent horror hits at similar points in their release cycles. The film's strong social media buzz, led by viral TikTok videos dissecting the trailers and speculating about the entity's true nature, has created organic marketing momentum that money can't buy.

What Success Means for the Genre

A breakout opening for "Other Mommy" would further validate Hollywood's renewed investment in elevated horror—films that combine genre thrills with strong performances and thematic depth. Blumhouse, which has produced the film alongside Universal, has built its reputation on this model, delivering critical and commercial successes like "Get Out," "The Invisible Man," and "M3GAN."

For Josh Malerman, another successful adaptation cements his status as a literary-to-screen powerhouse. Publishers are already positioning his upcoming novels as potential film properties, and studio development executives are reading his work the day it arrives.

As for Jessica Chastain, "Other Mommy" reminds audiences that she's equally comfortable delivering Oscar-caliber dramatic work and chewing scenery as a horror villain. Her dual performance in this film could become the kind of cult classic role that lives beyond opening weekend box office numbers.

October 9 will reveal whether "Other Mommy" achieves its projected $20-29 million debut. If it does, the film will join 2026's growing list of horror successes and prove once again that the genre remains one of cinema's most durable draws.