The Queen Anne's Return is a massive pirate ship with no castle-like elements to it. It seems to be a ghost ship, since the sails are tattered and there are holes in the hull. When the Gooper-statue in Glass Float is activated, the Queen Anne's Return sails through the wall. You must then climb up the ship to get inside. The ship will then sail far out into the ocean, and Gooper Blooper's boss fight will begin.
After Gooper Blooper is defeated, the ship will begin to sail further out, straight into a whirlpool. Cheating is the only way to survive. Bowser Jr. must be in the ship's rigging, Shadow Mario must be at the cannons, and Waluigi must take up a position at the wheel. When Waluigi Cheats, the three of them will become pirates and steer the ship out of the whirlpool. They will then sail it to a densely populated city with the Maskplex visible in the background.