Krypton is a fictional planet appearing in American comic books published by DC Comics. The planet is the native world of Superman and is named after the element Kryptonite. 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"). It has been consistently described as having been destroyed shortly after Superman's flight from the planet, although the exact details of its destruction vary by time period and writers. Kryptonians were the dominant species on Krypton.