Oggar, the World's Mightiest Immortal, is a fictional character from the publisher Fawcett Comics, whose publication rights were acquired by DC Comics in the 1970s. Oggar was a villain of Captain Marvel chronology in Pre-Crisis; he made no Post-Crisis appearances. He first appeared in Captain Marvel Adventures # 61 (May 1946, Fawcett Comics). His first appearance in DC Comics was in World's Finest Comics # 264 (August 1980). He was a major recurring enemy of the Marvels in the DC Comics stories published before the continuity-resetting Crisis on Infinite Earths miniseries in 1985.