Rouge made a bargain with the mermaid. She would give Amy legs for three days. During that time, Amy had to get Shadow to fall in love with her.
If he kissed her, she would remain hedgehog, but if not, she would turn back into a mermaid and belong to Rouge for the rest of her life
"You can't get something for nothing," the sea witch told her. "What I want from you is your voice!"
Rouge took Amy's voice and put it in her shell necklace. The mermaid would have to get Shadow to kiss her without even speaking to him!
