A dog had got a piece of meat.  He was carrying it home in his mouth to eat. He had to cross a plank lying across a stream. As he crossed, he looked down and saw his own shadow in the water. He thought it was another dog with another piece of meat.  He wanted it also.  He made a snap at the shadow in the water.  As he opened his mouth the piece of meat fell out, dropped into the water and was never seen anymore.