Polybius is a supposed arcade game that was released in the early 1980s in Portland, Oregon. The game was described as a Tempest-like puzzle shooter that caused health issues ranging from amnesia, night terrors, seizures, and even reports of people committing suicide. There were also reports of men in black taking data from the cabinets. A month after it's supposed release, the game disappeared. There is currently no evidence that the game even existed, but many have claimed to have seen or played it.
The first documented reference to the game was an anonymously authored ingression integrated to the site coinop.org on August 3, 1998. The ingression mentions the denomination Polybius and a copyright date of 1981, and its "About the game" describes the "bizarre rumors" that make up the legend. The author of the ingression claims in the description to be in possession of a ROM image of the game, and to have extracted fragments of text from it, including "© 1981 Sinneslöschen". The remnant of the information about the game is listed as "unknown". No credible source has ever claimed to have visually perceived a ROM image for the game. Conflicting information is even circulated regarding the style or genre of the game. The 1998 material claims that it is "weird looking, kind of abstract, expeditious action with some puzzle elements". Others describe it as an action space-fighter. For some, it has even been verbally expressed to be a shooter/puzzle game with some mazes thrown in, a coalescence of both.
Some speculate that the game grew out of hyperbolized and distorted tales of an early release version of Tempest that caused quandaries with photosensitive epilepsy, kinetics sickness, and vertigo. Author Brian Dunning notes that two players fell ill in Portland on the same day in 1981, one of them suffering from stomach pain after playing Asteroids for 28 hours in a filmed endeavor to break a world record, and the other collapsing with a migraine headache after playing Tempest at the same arcade. Dunning records that the FBI raided several video arcades in the area just ten days later, where the owners were suspected of utilizing the machines for wagering, and the lead-up to the raid involved FBI agents monitoring arcade cabinets for denouements of tampering and recording high scores. Dunning suggests that these two events were cumulated in an urban legend about regime-monitored arcade machines making players ill, and believes that such a myth must have been established by 1984, as it was referenced in the plot of the film The Last Starfighter, in which a teenager is recruited by a government agent who monitors him playing a covertly-developed arcade game.
According to an episode of a YouTube video based show by the name of Game Theory that focused on the game's alleged rumors and mysteries, series host and creator MatPat found parallels concerning the game's years of existence and to a period of time when the American CIA was said to have been engaged in experiments and activities to find if the administration of consciousness altering drugs, including the then new substance of LSD, were able to allow a form of mind control in combination with visual stimuli, particularly regarding the rise of video games and the technological ability of media allowing more intensive optical content. Theories include that the game's content in general was not the direct cause of the alleged side effects, but rather of undercover agents trained in legerdemain and other slight of hand techniques to slip in experimental drugs to players without their consent, and the administration of some variant substances through ventilation and a vaporous form around the machine.
In 2011, a Polybius machine was allegedly found in a Newport, Oregon storage locker. An unnamed person said that the game was recognizable from its "name on the side of what looks like an old Pac-Man game." The game reportedly vanished soon after its existence was revealed.
Despite the likelihood that Polybius never existed, the game has been featured in the season 18 The Simpsons episode, "Please Homer, Don't Hammer 'Em". It was also featured in Batman Inc. #1 as well as The Goldbergs in various episodes.