What’s the Origin of “Gedunk”?

Tom in Tallahassee, Florida, wonders why he and his fellow buddies called the store on a ship the gedunk, also geedunk, and also applied the word to the sweets and other goodies they purchased there. As Paul Dickson notes in his book War Slang, some servicemembers believe the word derives from the sound of a snack landing with a thud in a vending machine. More likely, though, it was inpsired by the gedunk sundaes mentioned in a popular cartoon from the 1920s called Harold Teen. This is part of a complete episode.