Justice League of America #13

In "The Riddle of the Robot Justice League!", the League is whisked to the mysterious lair of Sforll, who enlists them in a desperate mission to stop the villain Zed Brann from siphoning the universe’s vita-matter. Facing off against perfect robot duplicates of themselves, the heroes must prove their resolve before the fate of existence is undone. Written by Gardner Fox and illustrated by Mike Sekowsky, with inks by Bernard Sachs and lettering by Gaspar Saladino, this 1962 classic features a cover by Murphy Anderson.