One of video gaming’s craziest and earliest urban legends.

When video games became mainstream in the 1980s, they sparked lots of mass hysteria, with parents claiming that games did everything from make their kids violent to make them into lazy slobs with carpal tunnel syndrome. And then there was Polybius, an arcade game that supposedly hypnotized gamers and broke their brains.

Like any urban legend, this one was spread by word of mouth and it’s difficult to pinpoint where or when it got started. But if the story is to be believed, Polybius was a mysterious game produced by a company called Sinneslöschen that began popping up in suburban Portland arcades in 1981. It was supposedly very addictive, and within a few days, gamers began showing up in droves to play it. Fistfights even broke out in some arcades when people wouldn’t stop hogging the machines.

Polybius was so addictive because it was allegedly part of a government plot to test the psychoactive effects of video games on the public. The game’s flashing lights and subliminal messages could supposedly hypnotize and even brainwash gamers. Those who got hooked, the story goes, developed negative health problems ranging from insomnia to amnesia to extreme anxiety. Others claim that Polybius drove people completely insane and that government goons snuck into arcades at night to collect data and tweak the settings on each machine. (Also, sinneslöschen means “sensory deprivation” in German.)

Of course, all of this is complete hogwash. The game’s name itself is a reference to a writer from Ancient Greece who once argued that historians should never publish stories they can’t verify. There have been several attempts to debunk the rumors surrounding Polybius over the years. According to one, the legend was probably inspired by a 1981 incident in Portland when two players fell ill after playing Asteroids for 28 hours straight. Around that same time, an early version of Tempest caused some to get motion sickness and vertigo.

References to the legend have popped up everywhere from comic books to TV shows. A 2006 episode of The Simpsons featured Bart visiting an arcade filled with outdated games. He passes by a Polybius machine stamped with the words “Property of U.S. Government.” In 2013, a “homebrew” version of the game for the Atari 2600, produced by designer Chris Trimiew, debuted at the Portland Retro Gaming Expo. A group of filmmakers are also currently in the process of trying to make a documentary about the legend called The Polybius Conspiracy.