Maxwell is seen riding it on the top screen in the playground.
The Winged Dotted Bathtub is the official vechicle in Super Scribblenauts. It is just like a normal bathtub, but there are polka dots on it and it has (pink, to make it reasemble the artwork) wings. This object can also be created by any object with the adjective "Scribblenautical" or "Super" when they come in contact with Maxwell.