Mt. Bristle (Japanese: トゲトゲやま Mt. Spiny) is an unlockable dungeon in Pokémon Mystery Dungeon: Explorers of Time and Explorers of Darkness and Pokémon Mystery Dungeon: Explorers of Sky. It is unlocked after completing Drenched Bluff. It has nine floors plus a peak, where the player and his/her partner battle Drowzee to save Azurill.
In Mt. Bristle the following items can be found:
Apples always appear on all floors except on floor 5 where a big apple will appear instead. There seems to be no connection to items and floor.
The entrance to Mt. Bristle
Drowzee and Azurill at Mt. Bristle Peak