Polybius is an urban legend that emerged in early 2000, concerning a fictitious 1980s arcade game. The legend describes the game as part of a government-run crowdsourced psychology experiment based in Portland, Oregon, during 1981. Gameplay supposedly produced intense psychoactive and addictive effects in the player. These few publicly staged arcade machines were said to have been visited periodically by men in black for the purpose of data-mining the machines and analyzing these effects. Allegedly, all of these Polybius arcade machines disappeared from the arcade market.