How a Four-Sentence Bedtime Story Became the Horror Hit ‘Other Mommy’

Indie rocker and bestselling author Josh Malerman's latest nightmare-inducing novel sees a big-screen adaptation starring Jessica Chastain

Josh Malerman came up with the idea for one of the season’s biggest movies at the box office after his brother told him a brief story about his niece.

“I was on the phone with my brother some 13 years ago, and he told me that he and his wife had put their kid Elliott to bed for the night,” he says. Elliott replied in kind to her mother and father, then, eerily, said “good night” to her mom again. Her mom chided her gently: “You already said good night to me!” Then Elliott replied, face totally serious: “I was saying good night to Other Mommy.”

“My brother tells me this story, and I was like, ‘So what? Like, what hotel are you at?’ And he’s like, ‘No, kids say stuff, man,’” Malerman recalls. “Then it was like: ‘This is actually a book idea here.’ The goal is to keep or to maintain the same sort of shiver that I got from the four-sentence story my brother told me.”

At the time, Malerman was about to release his first book to hit screens, the 2014 novel Birdbox, which was optioned adapted into a 2018 Netflix movie starring Sandra Bullock about a mass suicide pandemic. Prior to becoming a full-time author, Malerman’s primary gig was his band, the High Strung, best known for performing the theme song for Shameless, “The Luck You Got.” Released in 2005, the song, written by Malerman, has amassed more than 17 million streams on Spotify. Appropriately, he and the band once set out on a tour of libraries in their home state of Michigan.

Malerman’s truly terrifying horror novel, 2024’s Incidents Around the House, upon which Other Mommy is based, tells the tale of struggling married couple Ursula and Ross and their young daughter, Bela. Presented from Bela’s point of view, the novel follows the child as she interacts with a mysterious entity in her closet that she calls “Other Mommy” and the creature’s infiltration into her family’s world. Other Mommy repeatedly asks Bela to “go into your heart,” and as her insistence grows, so does the terror infecting the family and those around them.

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According to Malerman, the book was optioned “lightning fast” by James Wan and Blumhouse-Atomic Monster, and began filming in Ireland in 2025 before the paperback edition even came out. When director Rob Savage signed on, Malerman was thrilled. Savage broke out in 2020 with his pandemic seance shocker, Host, which was almost entirely filmed via Zoom. Dashcam followed in 2021, about an obnoxious content creator on a fateful and terrifying drive, as well as 2023 Stephen King adaptation The Boogeyman. “I think that Rob has all these things in him,” says Malerman. “His first movie was all on Zoom. His second movie is totally batshit. And then his third movie is a big studio centerpiece, right? I think all of those elements are somewhere to be found in Other Mommy.”

Malerman was also pleased with the casting of Jessica Chastain as Ursula/Other Mommy. “Jessica Chastain encapsulated that frayed end of being not just a mother or a parent, but a parent that’s dealing with regular problems,” he says. “Time, job, love, affair, all these things, but now also dealing with an actual entity face-to-face in the house.”

Malerman says he bonded with the actress while visiting the set over their views on horror. 

“Jessica started talking to me: ‘You know, I’ve always seen horror as a feminist genre with the final girl and this and that,’” he recalls. “And then I was like, ‘Oh, I’ve always seen it as a Trojan horse between childhood and adulthood.’ And it struck me: I literally just met this woman, and we’re writing a treatise on horror together.”

Although the movie, which has grossed over $94 million worldwide, according to Box Office Mojo, doesn’t wholly cleave to the book — for example, the entity only mimics Ursula once in the novel, appearing mostly out of frame and vaguely humanoid — Malerman sees it as a worthy adaptation of his original work. He saw three cuts of it before the final, watching as Savage and the team swapped out different scenes from the source material. In the first cut, he says, the film included a scene in which the parents get drunk in the midst of running from Other Mommy, taunting the entity as they drank. “The first one felt very free-wheeling. A little bit of an indie filmmaker vibe to it,” he says. “They were very different versions.”

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From the jump, though, Malerman appreciated the care Savage took in his direction. He remembers calling the director after the first cut and raving that it wasn’t your typical grayscale horror film. 

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“Then Rob pointed out to me that it’s from the point of view of an eight-year-old,” he says. “I thought that was part of him maintaining that artfulness in a big movie.” He even found himself scared of his own creation: a jumpscare scene of Bela encountering Other Mommy in the bathroom. 

In the end, though, it was an interaction with the inspiration behind the whole thing that made it worth it. Elliott, his niece who coined Other Mommy, attended the premiere of the movie, and told her father how much it meant to her. “It was a bit like her childhood story had grown up into a huge movie,” says Malerman. “And I suppose it had.”