Swaying Ghost House, or Frosted Glacier-Ghost House, is the Ghost House level of Frosted Glacier in New Super Mario Bros. U. It is unlocked via completion of Scaling the Mountside or Icicle Caverns, and its own completion unlocks Wendy's Shifting Castle. The level also has a secret exit that unlocks Fliprus Lake.
In this Ghost House level, the rooms and objects slowly swing back and forth constantly, sometimes moving along with the screen when scrolled. The level begins next to a wall of Brick Blocks blocking a Warp Door. The screen scrolls left, where a Boo, a ? Block containing a power-up, and a P Switch are found. The P Switch causes Blue Coins to appear, and also turns the Brick Blocks into coins, allowing the Warp Door to be reached. The room that follows contains a pole, as well as ? Blocks and Brick Blocks that move as the screen scrolls up and down. There are two Warp Doors, which can be entered when the blocks line up with them. The bottom door leads to an area with a P Switch, causing Blue Coins to appear and turning Brick Blocks into coins. The top Warp Door leads to a room with more scrolling blocks. A P Switch is present, which allows the player to access a Warp Door located in the wall to the right. The next room has Warp Doors, as well as a moving row of coins that can be turned into Brick Blocks, allowing access to the doors. A Warp Door hidden in the wall leads to an area with a row of coins and a P Switch. The P Switch turns the coins into Brick Blocks, which move upwards whenever the player jumps. Big Boos and Circling Boo Buddies are encountered. The Warp Door at the top of the area leads to the Goal Pole.
- Star Coin 1: In the very first room, a P Switch must be activated in order to enter the wall and grab the Star Coin.
- Star Coin 2: In the third room, the player must enter the lower-left door. In the next room, the player should activate the P Switch, then run to the end of the room to use the Brick Blocks to reach the second Star Coin before the bricks turn back into Coins.
- Star Coin 3: In the fifth room, the player must once again hit the P Switch to turn the row of coins into Brick Blocks. If the player jumps fast enough, the player can discover a door hidden in the ceiling. The room there autoscrolls. The player must then use the P Switch to work their way through the room. If there is still some time left in the P Switch, the player must immediately Wall Jump their way up to the third Star Coin before the bricks revert back to coins.
The secret exit is in the same room the third Star Coin is located, just through the door in the far-right of the room.