The Argrathi were a humanoid species native to the planet Argratha in the Gamma Quadrant. Their government was known as the Argrathi Authority. As a form of punishment, the Argrathi implanted false memories of incarceration into convicted criminals. As the process was irreversible and tailored to each individual prisoner, the Argrathi claimed it to be more efficient and effective than maintaining a real prison system.
During a visit to Argratha in 2372, Miles O'Brien was accused of espionage by the Argrathi (because he was curious about their technology) and implanted with the memories of twenty cycle of imprisonment. Once they contacted Starfleet and learned they had acted overzealously to a man's honest curiosity, they freed O'Brien and offered an apology. However, it took O'Brien some time to overcome the PTSD the simulation put him through. (DS9: "Hard Time")