Mushroom Sea

The Mushroom Sea is a body of water that appears briefly in the The Adventures of Super Mario Bros. 3 episode Reptiles in the Rose Garden. The Mushroom Sea is located directly next to Bowser's Castle.

In Reptiles in the Rose Garden, Bowser banishes the White House (the capitol building of America, a country in the Real World) to the bottom of the Mushroom Sea after dominating the United States of America. This leaves America's President and his wife trapped in the ocean. Thankfully, Mario gains a Frog Suit and becomes Frog Mario just in time to save the Presidential couple. After a few mix-ups (including several with an ever-pursuing Jelectro), Mario finally makes it into the submerged house, letting in only a little of the outside water. However, being a member of the Super Mario Bros. Super Plumbing Service, he managed to think outside the box and find a way to get the capitol building to the surface: he built a pipe complex that shot the water outside and propelled the building upward. Thanks to Mario (who returned the White House to its proper place via one of Bowser's Airships), the President and his wife were saved.

After this long scene, the Mushroom Sea was never seen (or at least never referred to) again.