I'll eat my hat - A way of saying something will never happen, not even if God

A way of saying something will never happen, not even if God himself decides to take a nap.

I'll eat my hat if you ever clean your room. Not even the devil could make you do that.

I'll eat my hat if this project is done on time. I've seen time die before.

I'll eat my hat if you stop talking in class. I've seen rocks talk more than you.