An attention grabbing cover for Superman 198 (July 1967). Bates and Plastino open the story with the cover scene, as a man claiming to be the real Clark Kent arrives at the Daily Planet, and uses an x-ray gun to expose Superman.
It quickly becomes clear that this man knows a completely different Superman, one who came to Earth as a criminal adult, kidnapping Clark Kent and stealing his identity. Superman proves that he has always been Clark, and explains that the man must have come from a parallel universe.
He takes the man back to world, and gets into battle with the other Superman. But midway through he simply starts trashing the city, to the point where Superman intentionally causes a nuclear explosion to destroy Metropolis.
Superman had spotted some clues that made him realize that the Clark Kent and Superman were both androids, along with everyone else on the world. The entire thing was a huge trap set up by the Superman Revenge Squad, with satellites forming a force barrier that not even Superman can penetrate. So Superman simply flies out the gap the Revenge Squad left for their ship, and the Revenge Squad smash into the barrier, killing this group of them.
Heading back to the Daily Planet as Clark, he switches the x-ray gun with a projector, and shows Lois, Jimmy and Perry White how it makes anyone look like they have the Superman crest under their shirt.
Not the greatest story, but it does fulfill the cover.