Released last June, the book centers on eight-year-old Bela, who lives in a home strained by her parents' troubled marriage, only to see her life further upended by a sinister entity she calls "Other Mommy." When this malevolent presence emerges from her closet, persistently asking, "Can I go inside your heart?", Bela refuses. But soon, Other Mommy's manifestations become increasingly aggressive, threatening the safety of Bela's family.

Adapted for the screen by Nathan Elston (Succession), the film is being produced by Atomic Monster/Blumhouse in association with Malerman's Spin a Black Yarn. James Wan is producing, with Alayna Glasthal overseeing for his Atomic Monster. Exec producers include Michael Clear, Judson Scott, Macdara Kelleher, Savage, Malerman, and Ryan Lewis.

One half of lauded indie duo the Duplass Brothers, Jay recently returned to his writer-director roots for the first time in 14 years on The Baltimorons, a comedy that premiered at SXSW 2025. His latest film, See You When I See You, on which we were first to report, is currently in post-production.