A man walks into a bar and orders a beer. He takes his first sip and sets it down. While he is looking around the bar, a monkey swings down and steals the pint of beer from him before he is able to stop the monkey.
The man asks the barman who owns the monkey. The barman replies the piano player. The man walks over to the piano player and says "Do you know your monkey stole my beer." The pianist replies "No, but if you hum it, I'll play it."
The man repeats again "Your monkey nicked by beer....now, either give me three quid or I kill the thing"
The pianist, angered by the monkey, as this happened on many occasions, but this the first time anyone had not laughed at his joke, immediately killed the monkey.