The Bat-Mite/Mr.Mxyzptlk story was so popular that the team returned even before the Joker/Luthor team did, in World’s Finest 123 (Feb. 62), once again told by Coleman, Sprang and Moldoff.
It’s an excellent follow-up story. Superman, Batman and Robin are all quite secondary to the imps, as they come to Earth independently, but wind up mixing their magic, creating a creature that neither is able to stop, or unmake.
Everything the two 5th Dimensional beings do simply causes the creature to alter even further, creating more and more of a problem for the heroes, who are, frankly, all but useless in this tale.
The most they achieve is when Batman suggests that Bat-Mite and Mr. Mxyzptlk create a duplicate monster to deal with the first – conveniently, after the creature has become a living magnet. Creating a duplicate causes the two to attract, and destroy each other.