It happened that a Dog had got a bone and was carrying it home in his mouth to eat it in peace. Now on his way home he had to cross a plank lying across a running brook. As he crossed, he looked down and saw his own reflection in the water beneath.
Thinking it was another dog with another bone, he made up his mind to have that also. So he made a snap at the reflection in the water, but as he opened his mouth the bone out, dropped into the water and was never seen more.
You may lose what you have by grasping for more.