There is no significant change in the creative team on Superman in 1965, and yet pretty much none of the stories from this year are worthy of note. Action 322 (March 1965) is one of the only ones to use any of Superman’s established villains.
Jerry Siegel and Al Plastino are the ones behind this Superman Revenge Squad tale. They attempt to make Superman cowardly, but only succeed at making Clark Kent cowardly. This is not really noticible to Lois Lane, Jimmy Olsen, or any of Clark’s other friends.
It is disruptive for Superman, though, as he often acts bravely, while pretending to be scared, as Clark. He no longer has that degree of control over himself. So he works with his friends to try to make Clark a braver man.
It’s Supergirl who breaks him of the Revenge Squad’s effect, putting his uniform on over his Clark Kent clothes as he sleeps, so that he acts bravely as Clark without realizing it.
Another failed Revenge Squad plot.