Red Sauce Sea
From the Super Mario Wiki
The Red Sauce Sea is a giant sea, located in Pyramid Land from the The Super Mario Bros. Super Show! episode "The Ten Koopmandments". Though the sea appears to be filled with lava, it is actually filled with red tomato sauce.
Mario and his pals couldn't swim across the sea, so Mario used Koopa's magic stick to make a path through the lake; Mario then closed the path when King Koopa came.