A mysterious costumed crimefighter, his identity concealed by a yellow hood, who functions as the crimefighting ally of Superman much to the chagrin of Batman and Robin, who feel that their friend Superman has snubbed them in favor of a new partner.
When renegade scientist Lex Luthor breaks out of prison vowing revenge on both Superman and Metropolis, Batman and Robin volunteer their services to Superman in helping to re-apprehend him, only to be informed, somewhat curtly, that the Man of Steel has acquired a new crimefighting partner, Powerman, and that Powerman has demanded the exclusion of the Dynamic Duo from their crime-fighting team.
Stung at first by this rejection by their longtime friend and ally, Batman and Robin help apprehend Luthor anyway, only to discover that Powerman is in reality a costumed robot created by Superman as part of a well meaning ploy to discourage his good friends from risking their lives in the battle against Luthor (WF No. 94, May/Jun 1958: "The Origin of the Superman-Batman Team!").
(See also The Atoman of Earth-2)