Shimmer Desert is a place in Pokémon Mystery Dungeon: Explorers of Time & Explorers of Darkness. It has 10 floors to the dungeon and at the end of the dungeon the player must face Groudon. If you defeat Groudon you get the Terra Cymbal. If you have the Golden Mask you can then recruit it. Which is one of the seven treasures that you can get on Pokémon Mystery Dungeon: Explorers of Time & Explorers of Darkness. The dungeon can be unlocked by accepting a special mission.