An American filmmaker is suing the creators of popular Netflix series Stranger Things, alleging they stole the idea for the series from his 2012 short film, which was in turn inspired by a bizarre 1980s conspiracy theory.

According to TMZ, filmmaker Charlie Kessler claims brothers Matt and Ross Duffer ripped off his 2012 short film Montauk, a fictional film about the disappearance of a young boy and its links to paranormal activity at a nearby military base.

Much like Stranger Things, the film also features a troubled policeman, an alien-like monster and a portal to another dimension.

Kessler claims he pitched the idea of turning his film into a TV series to the Duffer brothers in 2014, but nothing came of it at the time.

The following year, Kessler alleges the Duffer brothers sold the concept to Netflix under the working title Montauk.

“Described as a love letter to the ’80s classics that captivated a generation, the series is set in 1980 Montauk, Long Island, where a young boy vanishes into thin air,” a 2015 Deadline article about the project read.

Stranger Things was also originally meant to be set and filmed in Montauk, but the setting was later changed to Hawkins, Indiana, and the show is filmed in Atlanta.

Of the name and location change, Matt Duffer told The Hollywood Reporter in 2016: “It was more practical than anything. We liked Montauk, because we liked the coastal setting, and Montauk was the basis for Amity, and Jaws is probably our favourite movie, so I thought that that would be really cool. Then it was really going to be impossible to shoot in or around Long Island in the wintertime. It was just going to be miserable and expensive.”

According to TMZ, Kessler is seeking monetary damages and the destruction of all materials copying his original content.

Kessler’s film was based on a long-held conspiracy theory that the US government conducted secret experiments on children at a military or air force base in Montauk in the 1970s and ’80s, with the goal of creating new psychological warfare techniques.

This so-called ‘Montauk Project’ was first detailed in a 1992 book titled The Montauk Project: Experiments in Time by author Preston B Nichols, who shared his supposed first-person account of working on time travel experiments at Camp Hero, a decommissioned Air Force base.

Preston B Nichols recalls seeing a ‘lizard man’

The details mentioned in the book – including children with psychic abilities and a “big, hairy monster” – have never actually been dismissed as fictional and the book has achieved cult-like status among conspiracy theorists.

Stranger Things also appears to have borrowed elements from the quasi-true Montauk Project story, though the Duffer brothers have never officially confirmed this.

One particular excerpt from Nichols’ book calls to mind Eleven, the telekinetic character played by Millie Bobby Brown on the Netflix series.

“With a lock of person’s hair or other appropriate object in his hand, Duncan [an alleged psychic] could concentrate on the person and be able to see as if he was seeing through their eyes, hearing through their ears, and feeling through their body. He could actually see through other people anywhere on the planet,” Nichols wrote, according to Thrillist.

Stranger Things character Eleven (centre) was kidnapped from her mother and taken to a military base to take part in mind control experiments for the US government. Photo: Netflix

The premise of Stranger Things also bears a resemblance to another classified US government project known as MK-ULTRA, conducted during the Cold War, in which the CIA illegally exposed unwitting human subjects to drugs like LSD, hypnosis and certain biological agents.

The goal was to develop mind control technology to keep up with the Soviet Union.

While the Duffer brothers have never explicitly spoken about their show’s similarity to MK-ULTRA or the Montauk Project, they have talked openly about borrowing elements of pop culture to create Stranger Things.

For example, the show’s opening titles are inspired by the covers of Stephen King’s novels, while the look and feel of the show is borrowed from Steven Spielberg’s ET, as well as anime and video games.

The Duffer brothers and Netflix are yet to make a statement regarding Kessler’s lawsuit. The third season of Stranger Things is currently in production, and will arrive on Netflix in 2019.