Bigfoot is a joke. It's a physical animal that is huge in a forest. No way with the technology today would we not find it.
Ghost are illogical.
Aliens are not probable. Plus if they existed they would be light years away.
God is not a physical being by definition. So, by discover it would be based on the evidence with leads to an existence of God. I personally feel we have that today.
"Excuse me sir, I see you have a weapon. Why don't you put it down and let's settle this like gentlemen" ~ max