A ruthless criminal whose various encounters with Batman, Robin, Superman, and Batwoman are described in World's Finest Comics No. 87 (Mar/Apr 1957: "The Reversed Heroes!") and in World's Finest Comics No. 90 (Sep/Oct 1957: "The Super-Batwoman!").
In March-April 1957 Superman narrates the story of his first encounter with the villainous Craig, which evidently took place sometime in the past. Superman recalls that, years ago, his father Jor-El had forseen the destruction of the planet Krypton and had made arrangements to transport himself and his family to Earth to begin a new life. Jor-El had also created some some special "radioactive capsules" which he hoped to bring to Earth with him. "Krypton is doomed," Jor-El had announced grimly, "--but when we migrate to Earth, we'll have super-powers there, because of the lesser gravity, and should anything on Earth make our powers fade away, these capsules will renew our super-powers temporarily!"
Even at that moment, however, the death of Krypton was at hand, and Jor-El barely had time to launch the infant Superman toward Earth in a tiny rocket before the entire planet exploded in a titanic roar. The metal box containing the radioactive capsules was never placed in the rocket, and when Krypton exploded it was sent hurtling into outer space, eventually finding its way to Earth embedded in a meteoric fragment.
Years after the death of Krypton, Elton Craig came upon the box of capsules while examining fallen meteors in hopes of finding some kryptonite to use against Superman. When Craig read the inscription on the metal box—"These radioactive capsules to be used only if needed to renew our super-powers on Earth. [signed] Jor-El"—and realized what he had found, he promptly swallowed one of the capsules and endowed himself with temporary super-powers which would last (according to World's Finest Comics No. 90 [Sep/Oct 1957: "The Super-Batwoman!"]) for a period of twenty-four hours.
When Superman became temporarily incapacitated by kryptonite during an encounter with the now super-powered Craig, he summoned Batman and Robin to Craig's hideout and asked them to swallow some of Craig's capsules to endow themselves with super-powers temporarily so that they could take up the battle against Craig while Superman recovered from the effects of the kryptonite. Because it was Craig who swallowed the first capsule, his super-powers faded first, thus enabling the super-powered Batman and Robin to capture him with relative ease. Soon afterward, Superman recovered his full powers, enabling Batman and Robin, whose temporary super-powers had by then faded, to return to their home in Gotham City (WF No. 87: "The Reversed Heroes!").
In September-October 1957 Elton Craig, the "most dangerous prisoner" at the Metropolis Prison, breaks out of jail and makes his way to the General Chemical Company, Inc., where he had managed to secrete one of Jor-El's special super-power capsules prior to his capture by Batman and Robin. Batman, Robin, and Superman all set out in search of the escaped Craig, but it is Batwoman who deduces that Craig may have hidden his super-power capsule at the General Chemical Company. Inside the plant, having come upon Craig about to swallow his capsule, she snatches it out of his hand and hastily swallows it herself in order to prevent him from getting it away from her. Then, aided by her temporary super-powers, Batwoman apprehends Craig and returns him to Metropolis Prison (WF No. 90: "The Super-Batwoman!"). (TGSB)