The Royal Tub (Location)

The Royal Tub is the king's personal giant bathtub which first appears in world three, though it also appears in world 4 but has been tipped upside down and converted into a hotel/shelter.

in level one you have to unplug the cork at the bottom to rid it of pirates. in the flash versions of world 3, there is a secret level down the drain that contains a star to collect, however this is omitted in the console editions. You cannot touch the pirates in the tub because they do deal damage.