The first Batman villain to take on both Superman and Batman solo in this book is Clayface, in a story by Wood, Mooney and Moldoff, in World’s Finest 140 (March 1964).
The story opens as a normal Clayface tale. Matt Hagen escapes from prison, douses himself in his potion,and begins a series of robberies that attract the attention of Batman and Robin. When Superman shows up, the story kicks into high gear. Clayface takes Superman’s form, and is able to duplicate his powers. It is not always the case that Clayface is able to do this, but his abilities were inconsistently shown.
Batman tries to take down the Clayface Superman with kryptonite, but Clayface just changes into a rocket and flies away. Still, the fact that he was susceptible to it gives Superman an idea.
The next time the Clayface Superman appears, Superman uses a piece of red kryptonite on him. It can only affect a Kryptonian once, so Superman knows he is safe. And he chooses a piece that causes the person affected to lose their mind. This makes Clayface much easier to beat, though they have to do it before he reveals Batman’s identity, which he discovered with x-ray vision. When the red kryptonite wears off, he has no memory of the experience, of or Batman’s identity.
This is the last appearance of the Matt Hagen Clayface before the New Look Batman begins, but he does return a few times in the pages of World’s Finest.
Green Arrow’s series in World’s Finest, which began back in 1941, comes to an end with this story by Bill Finger and Lee Elias.
The story is a variation on the old saw about a land where those who enter are trapped, but live forever. It’s Elias’ art that makes it a treat for the eye.
As the story ends, and Green Arrow and Speedy defeat the energy beats keeping everyone captive, this hero becomes homeless. Or bookless.
Green Arrow and Speedy would continue to appear as members of the Justice League of America and Teen Titans, respectively. Green Arrow would regain his solo series in this book in the late 70s, but his next time being in the same story with Speedy would be the classic Snowbirds Don’t Fly, from Green Lantern in the early 70s.