Cheerful Mermaid (ごきげんマーメイド) is a sound-activated, animated Hello Kitty plush from Takara, sold in Japan. It requires two N batteries, and appears to have been released in 2000.
Hello Kitty wears an iridescent, yellow flower near her left ear and two pink, iridescent seashells on her chest. She has a sparkly mermaid body and tail, which can either be blue or pink, decorated with shiny stars.
The blue version has a silver tiara with a pink gem, while the pink version has a pink tiara with the same gem.
Clap your hands, and she will flap her tail.