Robert Hayden. The Psycho-Pirate of Earth-2. Uses the Medusa Mask to generate emotions into another person's mind. During the Crisis, the Anti-Monitor enhanced his power and made him do all sorts of nasty things. He used to be a gangster who went to prison for attacking his abusive psychiatrist daddy and ran afoul of various members of the Justice Society of America.
After the Crisis was over, Hayden was imprisoned in a padded cell at a psychiatric ward. This was because he had gone insane, having retained full knowledge of the multiverse and the events of the Crisis. He did break out of the hospital once to try and take over Markovia, but he was stopped by the combined might of Infinity Inc. and the Outsiders. Once back in the asylum, the Psycho-Pirate showed the ability to manifest any DC Multiverse character that had been killed during the Crisis,and these characters were aware they were nothing but comic book characters. Animal Man intervened, and Hayden seemingly faded away into Limbo. One of the staff members, James Highwater, became the keeper of the Medusa Mask,and no one realized he wasn't Hayden. This incident is sometimes referred to as the Secret Crisis.
Not long after the events of ZERO HOUR, Hayden returned to reality and sold his soul to the demon Neron in exchange for more power. Unfortunately, this is a bad period for the Psycho-Pirate. The Medusa Mask was made into an eye patch, and the metal replaced half of his brain. He took to wearing a black leather jacket and matching outfit, and also seemed to be sane. He clashed with Chase Lawler, who was known as the Manhunter at the time, was defeated, and sent to jail.
When next he was seen, Hayden was insane once more, babbling incoherently about the existence of the multiverse. He and other inmates were freed by the Joker and ran amok, but eventually they were all rounded up and re-imprisoned. However, he once again escaped, only this time he went after the only other survivor of the original Earth-2: Power Girl. He tried to weaken her so she could be captured by Alexander Louthor of Earth-3, who wanted to use her in his plans to recreate the multiverse. Hayden was later killed by Black Adam, having his eyes gouged out and the Medusa Mask pushed through his head.
Sometime later, the Medusa Mask became an object sought in a mystical war, but the Teen Titan called Raven destroyed the mask.
And then came FLASHPOINT. In the newly rebooted universe, the Psycho-Pirate showed up as a member of the Twenty, a group of individuals infected with a psionic virus created by Brainiac. He sought out the Medusa Mask, hoping to use it to protect himself against other psychics. He then spent the following years hiding other telepaths from the H.I.V.E. organization, running afoul of Superman. He took over the minds pf various citizens of Metropolis and caused them to run amok, until Superman defeated him and incinerated the Medusa Mask with his heat vision. However, Hayden managed to escape.
And then came DC UNIVERSE REBIRTH. Now, the Psycho-Pirate is back to his insane original self, still babbling on about the multiverse and how something always keeps changing it. He is currently a prisoner of Batman, who is using him to cure the insanity of Gotham Girl, whom Hayden had driven crazy at the behest of Professor Hugo Strange.