He sets the duck on top of the biscuit tin on the bar and the duck begins dancing.
The barman finds this rather interesting as do the rest of the punters in the pub.
They all come round the duck and watch it for ages, and while doing so, buy more and more drink.
By the end of the night the bar is full of people watching this amazing duck, still dancing and giving the odd quack now and again.
The barman realises that he hasn't had business this good in a long time.
It is so good that he offers to buy the duck from the man to which the man agrees to sell for £500. The barman thinks it is a bit expensive but agrees to buy it anyhow.
On selling the duck, the man goes home leaving a crowded pub watching his dancing duck.
Later that night, the man gets a telephone call; it is the barman and he exclaims that the duck is a great success and that he has his money back in the amount of drink he has sold, but he says - "There is one thing... How do you get the duck to stop dancing?"
The man replies........
......."Oooh simple! -
Spoiler:
