The Galactic Golem
The Galactic Golem is the monstrous result of Lex Luthor's attempt to create life by collecting galactic matter into the form of a man. Infusing his creation with a hunger for the hyper-stellar energy that made its creation possible, Luthor then proceeds to implant that same energy into Superman, unbeknownst to the Man of Steel. A massive battle ensues, as the Golem ambushes Superman at a celebrity golf tournament. As the Golem saps Superman's very life force, Luthor makes it clear to Superman who was responsible for the assault, via a voicebox embedded within the Golem.
Finally, after a titanic struggle, Superman discerns the Golem's weak spot, a strange, swirling mark on its forehead. Superman strikes the spot with a massive blow, resulting in a cataclysmic explosion. As Luthor watches on in horror from his headquarters, it appears that the force has not only destroyed Superman, but every other being on the planet!
Luthor, devastated by the apparent death of his race by his own creation, plans to abandon Earth and its devastated landscape. As he prepares to leave, however, he finds himself under siege by the Galactic Golem! Without Superman around, it has traced back to Luthor the only other source of hyper-stellar energy, the cannon that Luthor had used to irradiate Superman. When it looks as if Luthor has doomed himself, Superman bursts into Luthor's hideout and pries the monster away from Luthor. While the Man of Steel grapples with the Golem, Luthor uses his cannon to imbue a passing meteor swarm with the energy the creature seeks. Superman launches the creature into space, allowing it to pursue its sustenance, ostensibly never to return. As Superman apprehends Luthor, he reveals that, prior to striking the Golem's weak point, he had used the energy emitted by the Golem to vibrate Earth's population to a different dimensional plane, in case the energy released ravaged the planet (S No. 248/1, Feb 1972: "The Man Who Murdered the Earth!").
Some time later, after depleting his store of energy in outer-space, the Golem is revived by alien scientists who lure him away from their own planet with "energy-charged meteoroids" that eventually find their way to Earth, followed closely by the Golem. Absorbing the energy of several meteors, the Golem seeks out Superman and the two engage in several battles. Finally, using Luthor's cannon to lure the Golem to his Fortress of Solitude, Superman manipulates the Golem over the magnetic North Pole and encases him in molten iron and nickel from the Earth's core. Encased in "elements highly attracted by magnetism" the Golem is transformed into a virtual statue, rendered immobile by "the magnetic pull of an entire planet" (S No. 258/1, Nov 1972: "Fury of the Energy-Eater!").