World 6-Castle (New Super Mario Bros. Wii)
From the Super Mario Wiki
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In this level, there are Spiked Balls that can hurt the player, and can also destroy Dry Bones. It is set above a pool of lava with moving platforms. The castle features two areas, the first area being composed of pendulum platforms that dip into the lava, and the second area being filled with Spiked Balls, which drop from the ceiling in vast numbers.
The player faces Morton Koopa Jr. again in this castle. The room's floor is composed of six stone pillars, which Morton uses in his offensive tactics. When Magikoopa casts his magic, at first nothing looks different except the stone pillars have slightly lowered. When he gets close enough to a player, he jumps and Ground Pounds, causing the pillars on opposite sides of him to shoot up to the ceiling, which kills the player if they get crushed. Morton also slides in his shell when hit, trying to hit players. Unlike his tower battle, Morton does not use his magic and his ground pounds do not stun players who are on the ground. Upon Morton's defeat by the third hit, the key to leave the castle appears.