Polybius is an arcade game which is said to have been released in 1981. The game can be mostly found in conspiracy theories and urban legends. An incident occured in Portland, Oregon in 1981. Several gamers played and the game became popular and the gamers became addicted. Those who played it eventually broke down and went insane and developed insomnia and suicidal tendencies. The urban legend says that Men in Black came into the arcade and collected some data from the machine.
The game was made by a gaming company called Sinnesloschen which is German for Loss of senses or Sense-delete and this has lead many conspiracy theorists to believe that the game was real and that it was a mind control project made by the U.S. government or that it was connected to MKULTRA somehow. This conspiracy is still strong today and has many believers