Bowser's Sky Castle

Bowser's Sky Castle is World 6-3 and the final level of Paper Mario: Sticker Star.

Mario first discovers the castle at the Gate Cliff after finding the other five Royal Stickers. By using them to flip a portion of the wall, the castle is unveiled. However, immediately after the castle flies up into the sky. After defeating Bowser Jr. on his airship, Mario reaches the castle.

Layout
Mario starts at the castle's front entrance, right outside. Entering the castle, the first room is a lengthy hallway. At the end is a door; opening the door reveals Kamek, who battles Mario. Defeating him allows access to the second room.

The next room contains conveyer belt-like carpet that activates when Mario steps on it; the carpet is full of holes, and on the underside is a pit of spikes. At one point, the belt stops, and the platform takes Mario to another platform. As soon as he steps off, the carpet falls.

In the next area, Mario and Kersti find Princess Peach, taped to a chain. Before Mario can peel the tape off, Bowser appears, who unveils a long hallway and challenges Mario to a battle. After defeating him, however, he falls off the tower at the end of the area, with the Royal Sticker. Seconds later, though, he returns as a giant made of cardboard. As soon as he is defeated like this, he returns to his normal state, allowing Mario to save Peach.

By the time Mario defeats the Giant Bowser, the castle has mostly been destroyed. As the game then cuts to the Sticker Fest, the castle's outcome is unknown.

Bosses

 * Kamek
 * Bowser

Enemies Assisting Bowser

 * Koopa Paratroopa
 * Bony Beetle
 * Spike Top
 * Hammer Bro.
 * Fire Bro.
 * Boomerang Bro.
 * Piranha Plant
 * Swooper
 * Whomp
 * Podoboo
 * Chain Chomp

Trivia

 * It is the only time in the series where the castle contains no regular enemies and instead only bosses, save for those assisting Bowser.
 * The castle's level marker stays red even if the player completes the game. It is however shown blue on the Prima guide.
 * The castle was planned to have mini-games to lengthen the level, but the idea was scrapped due to time restraints.