On a more positive note, the Germans would have been credited with wiping out tooth decay and gingivitis.
Now that right there is damn funny.
I vote for the Boomerang.
Not the plane, the Aussi Aboriginy Boomerang, if made of steel and thrown at low level attacking planes it probably would have bought down more than any bullets.
And it was flying / killing centuries before a P-51, or FW-190.
If you ever want to try hitting a red kangaroo at full speed with a rifle, it will just p!ss you off and waste ammo.
The little Abbo tracker beside you pees his pants laughing, pulls his stick out and snots the damn thing at 120 metres (paced out). A wee tad embarassing.