The Mermaid rescued Billy from a hammerhead shark attack and his uncle discovered her. They decided to hold on to her for a while, but Alexander tries to kidnap her for money. The other mermaids stop him and Billy and Sheena set her free. The next day, Dr. Deep decided to leave her alone so she'll be free.
She has long hair, wears sea shells for ear rings, and has clam shells covering her breasts. She has a long fish tail and all she says is "Kruu." Her favorite food are squids.