Castle Bowser

Castle Bowser is a form that Bowser takes on in Super Mario Bros. Wonder. The form is the combination of Bowser, his Koopa Clown Car, and Prince Florian's castle, created when Bowser comes into contact with a Wonder Flower in the game's opening cutscene.

After his transformation, Castle Bowser travels across the Flower Kingdom wreaking havoc, imprisoning Poplins in their Houses by truing them into fortresses, and is the main threat that Mario and his friends must stop throughout the game.