There is a show called Once Upon a Time about all the fairy tale characters getting cursed by the evil queen, and they were banished to present time and they can't remember who they are. The only person who can break the curse is a woman named Emma Swan. She broke the curse at the end of the first season. It is now in the fourth season. In the latest episode, titled "Poor Unfortunate Soul," there were many surprises. The first surprise is how Ursula became evil.
The story is revealed at the beginning of the episode when you find out that she wasn't always evil, and she started out as a mermaid. It all starts with her father, Poseidon, wanting her to use her singing voice to be like a siren, but she wants to use her powers to make people happy. She then steals a bracelet from him that would give her legs and she meets Captain Hook. He knows that she decided not to crash his ship, so he decides to take her wherever she wants in return for not killing him. Poseidon finds him and tells him that if he takes Ursula's voice then he will give him a way to defeat Rumpelstiltskin, which is a very long story if you want to know the story. He decides to take the shell and at first he considers not taking her voice, but then Poseidon shows up and Hook takes her voice. She then gives herself tentacles, and she swims away. In present day, Hook says that he would give her voice back if she turns good again. She agrees, but when they find the shell it doesn't work.
She throws Hook over board, and he is rescued by Ariel. He then finds out that her voice can only be returned by the person who enchanted the shell. Poseidon then gives her voice back, and she is good again and she leaves with her father. The last part is You get to find out what Mr. Gold's plan to get him, Maleficent, and Cruella De Vill their happy endings. It is to turn Emma evil because she is part of the reason why some people have their happy endings.