Once upon a time, there was a caveman who needed to kill another caveman. He jumped the other caveman, got punched in the face, they rolled around in the mud and eventually one of them rose up and roared in triumph, missing an eye, his shoulder dislocated, bloodied but victorious. The other lay dead on the earth, arm broken and his throat bitten out.
Once upon a time, there was a caveman. He sought to kill another caveman -- so he picked up a rock and smashed the other caveman's head from behind.
Once upon a time, there was a caveman. He wished to kill another caveman. He grabbed a long stick and sharpened one end and stabbed the guy in the guts with it.
Once upon a time, there was a caveman. He wished to kill another caveman. He sharpened a stick and threw it at him and it penetrated and the guy died.
Once upon a time, there was a caveman who wanted to kill another caveman. He killed an animal with his sharpened stick and extracted its guts and made an elastic string and tied it to a stick and sharpened another little stick and then shot one from the other and killed the guy.
Once there was a caveman and he lit a cannon with a match and launched a huge ball of metal to crush a bunch of the other cavemen.
Once there was a caveman who had a gun. He pulled the trigger and killed the other caveman.
And here we are!