A Bet You Couldn't See Coming
There was a guy who walked into a bar and said to the
bartender, "I'll bet you a beer that I can bite my left eye." And the
bartender said, Well, nobody can bite their own eye! Sure."
So the man took out a glass eye and bit it. So he got his free beer from the bartender who had just lost the bet.
Then he said, "I'll bet you another beer I can bite my right eye." And the bartender replied, "No one can have two glass eyes. Sure thing, Sir."
So the man took out false teeth and bit his right eye.