Well as soon as you kill your grandfather, you just vanish. If there was no one to conceive one of your parents, how could you be born? Your body vanishing is the time stream's way of saying don't worry, I fixed it. Sort of.BlackKraken said:kill my grandfather and then go back further and kill his grandfather and then try to go back to the point where i killed my grandfather and see what the universe tries to do to sort out that mess.
My guess, universe implodes.