Polybius is an alleged 1981 arcade game according to an urban legend whose origin can be traced to the year of 2000. The original game's actual existence has never been authoritatively proven, but it has served as inspiration for several free and commercial games by the same name.
The urban legend is that the game was part of a government-run crowdsourced psychology experiment, with gameplay producing 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. Finally, all of these Polybius arcade machines allegedly disappeared from the arcade market.
Polybius is thought to take its name from that of the Greek historian Polybius, who was known for his assertion that historians should never report what they cannot verify through interviews with witnesses.