Other Mommy: Five Biggest Changes From the Book Explained

The theatrical release of "Other Mommy" has drawn substantial attention, managing to lead the weekend box office despite mixed reviews from critics. Based on Josh Malerman’s 2024 novel "Incidents Around the House," the horror film centers on a sinister demon that befriends a little girl named Bela, played by Arabella Olivia Clark, while taking the appearance of her mother Ursula, portrayed by Jessica Chastain. While novels often provide deeper introspection, film adaptations frequently require dramatic restructuring to engage visual audiences. The screen version of "Other Mommy" is no exception, featuring notable shifts in character design, plot progression, and overall tone.

One of the most striking differences between the two mediums lies in the physical manifestation of the antagonist. In the film adaptation, the entity is remarkably skilled at mimicking humans for the majority of the runtime. Although it displays subtle tells such as facial drooping or slight levitation, it remains largely convincing as a doppelgänger. In contrast, the novel presents a far more unsettling and overtly unnatural entity. The book's version possesses an avian appearance, unstable facial features that shift unpredictably, and a putrid scent accompanied by an essence that induces coughing in those nearby.

Another major divergence occurs during a pivotal supernatural sequence involving a séance. In the movie, Grandma Ruth, played by Karen Allen, organizes a séance that inadvertently summons Other Mommy via a well-equipped yet naive ghost hunting squad. This results in a grim outcome as the investigators are unceremoniously killed. The book approaches this moment quite differently, utilizing a séance set up by fake spiritualists who quickly realize they are completely out of their depth and immediately admit their inability to help the family.

The setting for several key sequences also underwent substantial alteration to maximize visual impact on the silver screen. A memorable set piece in the movie takes place at an entertainment venue resembling Chuck E. Cheese, where Bela follows what she believes is a new friend. This leads to a terrifying scenario where she is pulled into an endless ball pit while her parents dive in after her, culminating in surreal transitions involving the family car. This cinematic sequence replaces a more grounded scene from the novel that takes place at a playground, demonstrating how filmmakers elevated the tension for trailer-ready moments.

Furthermore, the film incorporates heightened gore and altered narrative beats to escalate the dramatic stakes. In a particularly gruesome added sequence, a family friend named Frank invites the family to stay at his mansion following a disruption. Bela, sensing tension due to a secret affair between Frank and Ursula, is tricked by the demon into agreeing that the family would be better off without him, leading to a violent confrontation. These changes highlight the distinct storytelling demands of adapting horror literature into a mainstream cinematic blockbuster, offering fans of the book an entirely new experience.