I'm sure the idea for it came from the Pepperbox revolver. Retro, rather than futuristic. But, still it was an attempted evolution of the single-shot speargun, like the pepperbox was the evolution of the single-shot handgun.
Well, 2007 has come and gone. There should be plenty of these floating around somewhere. ;D
Silly humans, fins are for fish. Mammals use flippers.