Doraemon: Nobita's Great Battle of the Mermaid Kin (2010)

On Earth, Nobita's mom orders him to go shopping but he leaves to play pirates with Gian. His mother asks Doraemon and her husband but they have other plans. Doraemon ends up doing the shopping: When he reads the list at the very bottom he sees Dorayaki, a Japanese snack, his favourite food. Later Suneo shares his diving photo shoots in Palau with Gian and Shizuka. Nobita arrives to play pirates with Gian. Nobita wants to go to Suneo's house to see more pictures but they don't want him to. He cries and shouts Doraemon's name. Doraemon uses his gentle eyes to comfort him. When Nobita feels like diving in his town, Doraemon uses a Underwater Pump Simulator (架空水面シミュレーター・ポンプ) to pump all the water out of Tokyo, causing the entire city to go underwater. That night, Doraemon and Nobita use a Diving Mask Simulator to dive underwater.