She has a giant hermit crab shell on her back (as she was created from a shell) and can shoot ribbons that tie people together. Mimete took Undohkai with her to extract the Pure Heart of an athlete named Shun Hayase. After sucking out his Pure Heart and eating it, Undohkai attempted to run, but ran into Hotaru, who uses her power to blast her backwards. She was protected by her shell, but Sailor Chibi Moon used Pink Sugar Heart Attack on her, and Sailor Moon transformed into Super Sailor Moon and destroyed her with Rainbow Moon Heart Ache, leaving only the shell and Shun's Pure Heart.