It stars Theo James, Tatiana Maslany, Elijah Wood, Christian Convery, Colin O'Brien, Rohan Campbell, and Sarah Levy.

After stumbling upon their father's vintage toy monkey in the attic, twin brothers Hal and Bill witness a string of horrifying deaths unfolding around them.

[6] In March 2024, Tatiana Maslany, Elijah Wood, Christian Convery, Colin O'Brien, Rohan Campbell and Sarah Levy were revealed to have joined the cast.

[13] Perkins further stated that the comedy in the film intentionally avoids subtlety and makes use of extreme gore to joke about the absurdity, pointlessness, and randomness of death.

[18] In May 2024, Neon won a bidding war between multiple US distributors for domestic rights at the Marché du Film and set a theatrical release date for 2025.

[23] Brian Tallerico of RogerEbert.com gave the film three out of four stars and wrote, "Perkins has always been a formally confident filmmaker, but The Monkey contains some of his most striking imagery, shot through with malice by Nico Aguilar, and perfectly assembled by editors Graham Fortin & Greg Ng (who also cut Longlegs).