Kenkou Zenrakei Suiei-bu Umishou EP1 - Churaumi!

This introduces the characters and the setting. On the beach, Momoko Orizuka and Kaname Okiura are relaxing when a houseboat comes in. On that houseboat is Amuro Ninagawa. She is holding a three-foot long shark in her hand. She comes in and offers the shark to Momoko. Momoko refuses, saying she doesn't like a dead shark. Amuro says the shark is still alive. It then springs to life in Amuro's hand and tries to bite Momoko, but ends up tearing Momoko's bikini top off.