The Cat and The Birds

Once upon a time there lived cute birds in an aviary. There was a cat lived nearby house. That aviary was very near to the cat's house. Cat heard that the Birds in that aviary were ailing. 

So he got himself up as a doctor, and, taking with him a set of the instruments proper to his profession. He went to the aviary and presented himself at the door  to inquired about the birds health. I am coming to checkup all of your health. Would you like to allow me to go inside and check you? “We shall do very well,” they replied, without letting him in. When we’ve seen the last of you.”

Moral: A villain may disguise himself, but he will not deceive the wise.