Once upon a time, there were some cute birds living in a big birdhouse. Close to that birdhouse lived a cat. The birdhouse was really close to the cat's home. The cat heard that the birds in the birdhouse were not feeling well.
So, the cat had an idea. He dressed up like a doctor and took some tools that doctors use. He went to the birdhouse and stood at the door. He wanted to ask about the birds' health. "Hello, I've come to check on all of you. Can I come inside and examine you?" he asked.
The birds didn't believe the cat and replied, "We'll be just fine without your help. You can leave now." They didn't let the cat inside. "We'll be better off without you here," they added.
Moral of the story: A bad person might pretend to be someone else, but they won't fool smart people.