Ninja stars really have two different variations. One of them is designed more-so for actually killing a person, and is meant to be thrown directly at them, as one would a knife or axe, for instance. The other is designed to bounce around and leave cuts (some times being poisoned on the edges, so a small cut becomes fatal).  In either case, though, ninja stars don't have any sort of boomeranging quality to them, and I don't see how making it bigger would be able to add that.<br/><br/>Even a war boomerang doesn't return to its throwers arm. Australian aborigines used them. Long sticks of heavy wood that were balanced for throwing. Could easily break an arm or a leg, or someone's neck. But, their's no realistic way to hit a target like that and have it come back to you; physics do not work that way.