Unknown Dungeon (Kalos)

The Unknown Dungeon (Japanese: ななしの Nameless Cave) is a very small cave in southern Kalos that can be accessed from Pokémon Village. A sole resides in the center with a game-specific Mewtwonite. The Unknown Dungeon is only accessible to s who enter the Hall of Fame. is needed to access the cave.

Its purpose as a place to catch Mewtwo is a direct reference to Cerulean Cave in Kanto. It also shares its name with the alternative moniker for Cerulean Cave used in all language releases of the Generation I games.

Geography
The Unknown Dungeon is a tiny cave whose entrance is found in the side of a mountain. The cave is barren in terms of terrain aside from the occasional water drop and the few rocks that dot the floor. awaits the player in the center of the cave, facing away from the entrance.

In the Pokémon Adventures manga
The Unknown Dungeon appeared briefly in Malamar Traps, where was shown residing inside the cave, waiting to make its move against Team Flare.

In other languages
Mazmorra Rara (Kalos) Grotte Inconnue (Kalos) Grotta Ignota (Kalos) 無名洞窟（卡洛斯）