Microwave Man
A man named Lewis Padgett who returned to earth as an old man in October 1980 after forty years of space travel aboard an alien spacecraft. Before he left the earth Padgett had been the costumed villain Microwave Man. Upon his return Padgett calls upon his alien friends to grant him his youth back even though it would shorten his remaining life to only a few hours.
Once he is young, Padgett once again assumes the identity of Microwave Man and challenges Superman. The aliens inform Superman that Padgett only wants the glory of defeating him and will soon die. Superman allows Padgett to defeat him in a test of strength after which Padgett dies satisfied and the aliens claim his body to set adrift in space as he had requested (Act No. 488: "Superman Battles Microwave Man!").