Update (April 4, 2018, 12:48 p.m.): Alex Kohner, attorney to the Duffer brothers, has issued the following statement about the lawsuit:

“Mr. Kessler’s claim is completely meritless. He had no connection to the creation or development of Stranger Things. The Duffer Brothers have neither seen Mr. Kessler’s short film nor discussed any project with him. This is just an attempt to profit from other people’s creativity and hard work.”

The original story continues below.

Matt and Ross Duffer are entering the upside-down world of litigation—and no, not because Stephen King and Steven Spielberg have finally changed their minds about the duo jocking their aesthetic. Filmmaker Charlie Kessler has filed a suit claiming that the duo stole the idea for the hit Netflix series Stranger Things from his 2012 short film, Montauk, and is now seeking monetary damages and a jury trial. The suit was filed Tuesday in the Los Angeles Superior Court, according to Deadline; you can read it here.

Kessler claims that he presented his idea to the brothers at a 2014 Tribeca Film Festival party, and that it was based on his short film Montauk, which debuted at the Hamptons International Film Festival in 2012. Kessler says he wanted to develop the short into a feature film titled The Montauk Project, and that he gave the Duffers “the script, ideas, story, and film” to flesh out the idea—which they allegedly took and spun into the series Stranger Things. As Deadline notes, it’s true that Stranger Things was originally pitched to Netflix with the title Montauk, and was set in Montauk, Long Island—though it was later transplanted to the fictional town of Hawkins, Indiana.

The sci-fi series is set in the 1980s, and its first season revolves around a group of precocious teens searching for their missing friend. They recruit the help of a strange new girl in town who has telekinetic powers after being subjected to nearby military experiments. On their journey, they stumble into a monster from another dimension called the Upside Down. Kessler’s Montauk is also about a missing boy, military experiments on kids, and a monster from another dimension, Deadline reports. According to Variety, the film was made found-footage style; Stranger Things does not use a similar conceit.

That said, there’s also another similar project that predates both Montauk and Stranger Things. Per Variety, a 1992 book titled The Montauk Project: Experiments in Time, written by Preston B. Nichols and Peter Moon, is about a series of secret government experiments at Montauk’s Camp Hero State Park, which conspiracy theorists believe really happened. Stranger Things star Gaten Matarazzo noted the inspiration in a 2017 interview with Wired, saying the show was somewhat based on those Camp Hero experiments. The plot thickens.

Representatives for the Duffers and Netflix have not yet responded to Vanity Fair’s requests for comment.