Switchblack Ruins

Switchblack Ruins, or , is the second course in the seventh world of Super Mario 3D World, World Castle. It becomes accessible by beating Fort Fire Bros., and its own completion unlocks Boiling Blue Bully Belt.

Layout
The level starts in a dark hallway that leads to the first set of Switch Panels and a Spiny. Activating the Switch Panels opens up the path to some Question Blocks and the second set of Switch Panels guarded by two Spinies. Stimulating this set of Switch Panels leads to the level's Checkpoint Flag, the third group of Switch Panels and a Fire Piranha Plant. A moving platform takes the player to the final Switch Panel set, guarded by four Spinies and two Fire Piranha Plants. A nearby pipe leads to the Goal Pole.

Green Stars

 * Green Star 1: In a circular room before the checkpoint, the player must use the Fire Flower to light all four torches to reveal the green star.
 * Green Star 2: Immediately after the checkpoint, the player must keep going right to find a hidden room with the green star.
 * Green Star 3: The third green star is behind the green Warp Pipe near the end of the level. The player needs to unveil an invisible rectangular ? Block to reach it.

Stamp

 * In the second volcanic room, the player has to jump to the rightmost platform to find the stamp.

Enemies

 * Spinies
 * Fire Piranha Plants