Claim: DC's Sun Boy first appeared in Action Comics #276 and was created by Jerry Siegel and Jim Mooney.
Evidence: Sun Boy is a fictional superhero in the 30th and 31st centuries of the DC Comics universe. Action Comics # 276 (May 1961) Jerry Siegel
Jim Mooney 
Sun Boy first appeared in Adventure Comics #276 and was created by Jerry Siegel and Jim Mooney. DC Comics