Earl Garver was a brilliant scientist who threatened to blow up Metropolis.
Garver was a scientist at S.T.A.R. Labs who stole a radioactive isotope. He made a bomb out of it, hid it in lead, and held Metropolis for ransom. In response, the SCU raided his house, but were unsuccessful. Superman did breach the heavily fortified villa, and confronted Garver. However, he had set another trap, and a large piston fell down upon Superman. The building was not strong enough to bear the massive pressure Superman applied on the piston, and a loose cable hit Garver, knocking him unconscious.
With Garver comatose, the SCU had major worries about the bomb, so they took a desperate step. They tried to let the Parasite read his mind, but it was so overwhelming that Garver took control of him. Stuck inside Parasite's mind, Garver lead Maggie Sawyer and Superman to a false location of the bomb, while he planned his escape. He reasoned with Jones, and offered him a way to retain the absorbed power forever. Jones agreed, and "Parasite" escaped the hospital.
Garver changed the ransom demand: Superman had to drop the money off at an abandoned subway tunnel. He agreed and followed the instructions, but "Parasite" ambushed him. Even without his full powers, Superman was able to hold off "Parasite". During the fight, "Parasite" changed the plan yet again: he reactivated the bomb, and set the timer to two minutes. Since Garver's body was miles away, "Parasite" planned to blow up the tunnel, Superman, and Jones. Faced with death, Jones fought Garver inside Parasite's mind but Garver won. When Superman threw the bomb into a deep pit, he and "Parasite" fell in after it, and the explosion knocked "Parasite" unconscious, giving him his own mind back.
Eventually, Garver woke up from his coma. Thinking to be still safe in an ambulance, he was surprised when Superman had carried the ambulance to Stryker's Prison.