Sofia The First Toy Mermaid dolls with Disney Princess Sofia and Mermaid Ooona. Sofia The First uses her amulet to transform Ariel and herself into Mermaids. Sofia and Ariel meet the Oona figurine. Oona is a character in the Sofia the First special Sofia the First episode The Floating Palace. She is a mermaid who befriends Sofia, and gets kidnapped by Cora an evil Sea Monster. In this toy review video, Plankton from Nickelodeons SpongeBob SquarePants and evil pirate Pete from Mickey Mouse Clubhouse capture a magic pearl to steal the recipe for crabby patties from Mr Crab and Sponge Bob. Mermaid Sofia the First, Oona and The Little Mermaid save the day and get the magic pearl back.