The Wolf In Sheep's ClothingShort Story by Aesop
A certain Wolf could not get enough to eat because of the watchfulness of the Shepherds. But one night he found a sheep skin that had been cast aside and forgotten. The next day, dressed in the skin, the Wolf strolled into the pasture with the Sheep. Soon a little Lamb was following him about and was quickly led away to slaughter.
That evening the Wolf entered the fold with the flock. But it happened that the Shepherd took a fancy for mutton broth that very evening, and, picking up a knife, went to the fold. There the first he laid hands on and killed was the Wolf.
The evil doer often comes to harm through his own deceit.