Polybius was an arcade cabinet was released in incredibly limited numbers in the early 80s.
While that's not strange on its own, what was bizarre was how the game was only released in a few neighborhoods in the surrounding areas of suburban Portland, Oregon. Polybius would cause players to suffer vivid nightmares and, in some cases, suicidal tendencies.
Thanks to a violently powerful strobe effect in the cabinet, players would also find themselves fighting epileptic seizures. Polybius vanished and has retired to the realm of conspiracy. Some believe the cabinet was released by DARPA (the same government agency behind MK-Ultra and those killer robot videos you see all over YouTube) to test response to psychoactive machines. Even stranger are reports that once a week men dressed in black would come through and collect the data stored on the game's memory.
You can watch the video above to see what Polybius looks like with some of the command options available to arcade owners/government agents.