Fusion Cricket Ball

If you were to throw a cricket ball at 10 million miles per hour (a small fraction of the speed of light) , it would cause the air Infront of it to undergo a nuclear fusion reaction. The ball and the air Infront of it would turn into super heated plasma and detonate as a thermal nuclear explosion. 

The thermal nuclear explosion would vaporise everything in the area including the ball and the person throwing the ball along with the air in the ball's path.

The good thing is no one can ever throw a ball that fast, the energy required to push the ball at that speed would be enormous, perhaps comparable to the output of an entire power station over a short period of time.