Superman and Batman get the best villain they have yet faced together in World’s Finest 98 (Dec 58), by Finger, Sprang and Kaye, the Moonman.
An astronaut, just called Rogers, orbits the Earth, but his ship passes through the tail of a green comet. When he returns to Earth, he finds that, when the Moon shines on him at night, he gains super-powers, and an evil personality. The powers are magnetic in nature, but as the comet had kryptonite in it, he also becomes toxic to Superman when in his Moonman guise.
Sprang has a lot of fun on the art, and Rogers is a reluctant villain, appalled by his own actions. He tries to turn himself in, but gets captured by criminals, who hold him until the Moon causes another transformation. Really, the only reason Superman and Batman triumph in this story is that the effect of the comet simply wears off.
A villain with a lot of potential that was not made the most of, Rogers would not return to these pages until 1980.