Bonus challenge (Luigi's Mansion: Dark Moon)

Bonus challenges are small pocket levels that appear in Luigi's Mansion: Dark Moon. They can be accessed only via portals that often appear inside furniture or objects, and they teleport Luigi into the ghost dimension when he interacts with them. They usually leave him on small floating islands or in small mazes.

To access a bonus challenge, Luigi has to locate a shaking door. Shaking doors can be found on fridges or coffins or as fake doors, and they are usually hidden from view or behind fake walls, requiring the player to hunt them down. Opening a shaking door pulls Luigi into a smaller level, where he must complete a set of tasks or minigames within a set time limit; these range from collecting several Red Coins and normal coins in a maze to finishing a snowman's face to capturing five Gold Greenies before they escape to having a snowball fight with some Hiders. The minigame ends when time runs out or Luigi completes the given objective, the latter of which rewards him with a gem or a large amount of treasure, and he gets returned to the area he used to access the dimension.