There once was an alchemist in a small, countryside village. She was given the job as village doctor and she was the best at what she did. Merchants from across the land would visit her, asking for her divine medicine. She would decline every time. Her medicine shall remain only in her village.

Once, a villager came in with a complaint. "After you gave my son medicine, he grew cat ears!" He yelled. The alchemist shook her head, while the apprentice looked on with disapproval. The doctor declined any link to the incident with the boy. "Correlation isn't causation," the woman calmly replied. Eventually, the irritated man left.

More and more complaints started to come in. "My daughter is now a man!" "My husband turned into a lizard!" "My brother breaths fire!" And many more complaints did the villagers say. Yet, every time, she would tell them that correlation isn't causation.

"Why do you practice all your potions on your customers?" The apprentice asked one day. The lady shook her head. "I test your potions," she corrected her. "Now, some tea if you may."

The apprentice started to brew her tea. The young boy decided to teach her a lesson. He spiked the tea with a potion: a potion with unknown effects.

When the witch doctor took a sip, her eyes grew wide. She then shook her head and started laughing. "What did you do?" She asked. "I'm not sure. Maybe a mirror would be required," the boy replied with a smirk on his face.

The apprentice went to get a mirror. When he returned, the fiendish alchemist was in shock. She had a pair of ears and a tail. Her face had been completely changed from what it had used to been. Her hair was matted and her skin was brittle and dry.

The witch doctor looked at her apprentice and sighed. "Lesson learnt."