Old Chateau

The Old Chateau is a dungeon in Sinnoh. It has 64 tiles arranged in an 8x8 square, including 8 chest tiles, 19 non-boss encounter tiles, and 1 boss encounter tile.

Pokémon

 * Gastly
 * Haunter
 * Gengar
 * Rotom (boss)

Catching Rotom unlocks its forms:
 * Rotom (heat) (boss)
 * Rotom (wash) (boss)
 * Rotom (frost) (boss)
 * Rotom (fan) (boss)
 * Rotom (mow) (boss)