Pokémon Gold and Silver/Mt. Mortar

Mt. Mortar is one of the bigger dungeons in this game and although it holds a bunch of items (some better than others), the most interessting thing about the mountain is that you can get a Tyrogue, which can evolve into three different Pokémon (Hitmonlee, Hitmoncahn and Hitmontop) based on its stats at level 20. Unfortunately, you are only able to reach it after you can use Waterfall (8th badge).

Pokémon Found

 * }
 * Marill encounter rate is much higher during swarms

Pokémon Found (Water)

 * }

Pokémon Found

 * }

Pokémon Found

 * }

Pokémon Found

 * }