 The planet was created by Jerry Siegel and Joe Shuster, and was first referred to in "Action Comics" #1 (June 1938).The planet made its first full appearance in "Superman" #1 (summer 1939).Krypton is also the native world of Supergirl, Krypto the Superdog, and Power Girl (in her case, an alternate-universe version designated "Krypton-Two").