The Origin of Captain Boomerang
George "Digger" Harkness is a supervillain traditionally portrayed as an enemy of the Flash.
Secretly the illegitimate son of an American soldier and an Australian woman, Harkness was raised in poverty, during which time he developed great skill in making boomerangs, and in using them as weapons. As a young adult, he was hired as a performer and boomerang promoter by a toy company which was, unbeknownst to him, owned by his biological father. Audiences ridiculed him, and a resentful Harkness turned to using his boomerangs for crime. He originally became Captain Boomerang as a mascot for a Toy Company and briefly pretended another man was impersonating him, showing his 'parents', (really other crooks) to the Flash after the Flash caught him next to a crime scene. He nearly succeeded in killing Flash after knocking him out with a boomerang, then tying the Flash to a giant boomerang he fired, so that it was sent into space then fell into the ocean, but Flash vibrated so fast and increased the boomerang's velocity so much he was able to free himself from his friction-proof bonds and jail his foe and the two crooks.
Although he lacked any actual superhuman abilities, he became a recurring enemy of the Flash, typically by devising altered boomerangs which could produce astonishing effects (some would explode, others had razor-sharp edges, etc.), and using them ruthlessly. He became a staple member of the Rogues, a group of villains dedicated to opposing Flash, and who were first organized after Gorilla Grodd broke them out of jail. Though captured when Flash made their weapons hit each other, they continued to act together.
Throughout the first several years of the character's existence, Captain Boomerang spoke with an American accent. Beginning in the late 1980s he developed an Australian accent.