The drunken snake!

Arriving at the edge of the river, the fisherman soon realized he had forgotten to bring any bait.  Just then, he happened to bump on a small snake with a worm caught in its mouth.  Suddenly the fisherman snatched up the snake and robbed him of his worm.

Feeling sorry for the little snake with no lunch, the fisherman picked
him again and poured a little beer down his throat.  Then he got down to fishing.

An hour or so later, the fisherman felt a tug at his trouser leg.  Looking down, he saw the same snake with three more worms in its mouth.