If God showed up tomorrow and stopped a Tsunami from killing hundreds maybe thousands, 40% of the people (most in China) will insist He is an alien.
If He showed up and announced His Being every agent in Hollywood would look to sign Him, every lawyer would file suit against Him for some reason or another. Every church would suddenly be filled to capacity. Wars would start whether or not He called himself Jehovah or Allah.
You want me to prove that God exists, I say go ahead and create something that doesn't.