The foolish boy
Once, a boy went to a pond to catch fish. He lay down on the shore of the pond and put his left arm inside the pond. Then he waited for the fish to fall into his trap.
Just then he felt as if some fish had caught his hand. He took out his arm and saw that it was not a fish but a snake. At once, he shook his hand and the snake fell into the water again.
An old man watching all this, came to him and said, "Always think twice before doing anything. Doing foolish things can sometimes cost you your life."