The “Stranger Things” universe is expanding at Netflix, with the Duffer Brothers lining up multiple projects within the world they created for the series.

Under their overall deal with Netflix, the Duffers — Matt and Ross — have established the production company Upside Down Pictures, bringing on Hilary Leavitt to run the company.

Among the new projects they have in development, the Duffers are officially working on a “Stranger Things” spinoff series, though exact plot details remain under wraps. The show will be based on an original idea by the Duffers with Upside Down Pictures and 21 Laps producing. The Duffers have previously said that the show would not focus on characters like Eleven or Steve Harrington.

In addition, a stage play set within the world and mythology of “Stranger Things” is in the works. It will be produced by Sonia Friedman, Stephen Daldry, and Netflix. Daldry will also direct. Kate Trefry will write. 21 Laps serves as associate producer.

“Matt and Ross are an exceptionally unique talent with a vision so crisp and clear,” said Ted Sarandos, co-CEO and chief content officer of Netflix. “They are all about the details — it’s no accident that ‘Stranger Things’ has pierced the zeitgeist to become the epic pop culture phenomenon it is today. We’re excited to continue telling new stories with them as they grow Upside Down Pictures and to welcome Hilary as creative partner.”

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The Duffers are also working on a live-action TV version of the Japanese manga and anime series “Death Note.” The series was previously adapted into a live-action film in 2017.

They are also at work on a series adaptation of Stephen King and Peter Straub’s book “The Talisman” alongside Steven Spielberg’s Amblin Entertainment and Paramount Television, with Curtis Gwinn adapting the book for the screen. Development on that series was first reported in March 2021. Finally, the Duffers are producing an original series from Jeffrey Addiss and Will Matthews, the creators of the Netflix series “Dark Crystal: Age of Resistance.”

“It didn’t take long into our first meeting with Hilary, where we bonded over films like ‘Jaws,’ ‘Home Alone,’ and ‘Speed,’ to know we had found a kindred spirit,” the Duffers said. “Hilary’s passion for storytelling is perhaps matched only by her passion for the storytellers themselves, for whom she is fiercely protective. No wonder so many writers and directors are drawn to working with her. She is a rare talent indeed, and we feel extremely grateful to have her at our side as we build Upside Down Pictures”

“Stranger Things” Season 4 debuted its first seven episodes on May 27, with the final two episodes of the season dropping on July 1. The show recently became the second Netflix series ever to cross the 1 billion hours viewed mark.

“I remember the first movie I saw in the theater, the first VHS tape I got for Christmas, the first international one-sheet I bid for on ebay because it was cooler than the domestic,” Leavitt said. “And the first time I met Matt and Ross. All of these seminal moments have led to this ridiculously cool opportunity to build a company with the Duffer Brothers where we produce movies and television because we love movies and television. This love is at the core of Upside Down Pictures, where we’re able to collaborate with other artists on projects across the full spectrum of genre. We all love what we do and are excited to do more and more.”

The Duffer Brothers are repped by CAA and Alex Kohner at Yorn Levine.