Doraemon The Movie: Nobita's Great Battle of the Mermaid King (映画ドラえもん のび太の人魚大海戦, Eiga Doraemon Nobita no Ningyo Daikaisen?), also known as DORAEMON THE LEGEND 2010, is a 2010 Japanese animated film that was released on March 6, 2010. This movie is part of the celebration for the franchise's 40th anniversary and it's 30th movie anniversary (映画ドラえもん30周年?).
When Nobita feels like diving in his hometown, Doraemon uses Underwater pampu Simulator (架空水面シミュレーター・ポンプ?) to pampu all the water to fill up water. That night, Doraemon and Nobita use a Diving Mask Simulator to dive underwater. Later on, lots of fish, and a papa attack Doraemon and his friends. So, Doraemon puts a stop on the Underwater pampu Simulator, but there is a girl named Sophia, lay down on the bushes in his town.