El Gar-Kur was a Kryptonian criminal from Kandor who was a double for Jimmy Olsen. He used a machine to exchange places with Olsen when Superman took his friend to visit the Fortress of Solitude. El Gar-Kur masqueraded as Jimmy and began to cause damge and destruction, eventually trying to kill Superman with kryptonite. Superman, meanwhile, had deduced that this 'Jimmy' was an imposter, and had tricked him with fake kryptonite. However, it took the Kandorian Police using the machine to swap back the real Jimmy and his doppelganger to bring about a satisfactory conclusion.
