Updated

The Duffer Brothers have been sued for allegedly stealing the idea for “Stranger Things.”

Producer Charlie Kessler alleged that Ross and Matt Duffer ripped off his 2012 short film, “Montauk,” which features government experiments of a supernatural nature as a major plot point.

In documents obtained by TMZ, Kessler claims that he pitched the film, which won an award at the Hamptons International Film Festival in 2012, to the brothers as a full-blown series called “The Montauk Project” in 2014.

The Duffers rejected Kessler’s offer, but he claims that they went on to use his premise, script, story and title for “Stranger Things.”

The hit Netflix series premiered in 2016. Its second season dropped in October 2017.

Kessler’s “Montauk,” meanwhile, may have been inspired by true events.

“After World War II, the United States recruited Nazi scientists and used them for a variety of things, to develop weaponry and technology,” researcher Christopher Garetano, an executive producer of the History Channel series “The Dark Files,” told The Post.

Garetano researched The Montauk Project for over a decade and claimed that the government recruited runaway children on whom to perform illegal experiments in time travel, remote viewing and mind control, similar to those performed in Project MK Ultra.

Many of these experiments allegedly occurred at the Camp Hero Air Force Base in Montauk.

A rep and attorney for the Duffer Brothers did not immediately return requests for comment.

This article originally appeared in Page Six.