Crystal Ruins

Crystal Ruins, commonly referred to as CR, is an Ice-type dungeon located in Winden, northwest of Snowbasin Town. To access it, you must have Rock Smash. The only weather conditions that occur here are clear and hail weather.

Crystal Ruins is one of the older dungeons in the game, and along with Crystal Castle was the first dungeon to be added to Winden after its release. It was once the hardest non-event and non-set-level dungeon in PMU 7. On June 18th 2019, both Crystal Ruins and Crystal Castle received a revamp.

The Pokémon in this dungeon are mainly in the level range of 35-41, though Gastly spawn lower, and Regice is level 60.

Floors 1-8
The walls are crystal-like and dark blue with some green crystals scattered around. The floor is a light-blue stone, with some blue rocks here and there.

Floors 9-17
From Floor 10 upwards Regice has a chance to spawn, although in rare cases it will make a surprise attack. Regice can drop an Ice Diamond, TM Ice Beam, or its Heart Slate. It spawns at level 60 and has the moves, Ice Beam, Zap Cannon, Hyper Beam, and Icy Wind.

On Floor 15 is a Sealed Chamber with a Shiny Box that can contain a Clear Silk.

Floors 18-20
...

Secret Room
Secret Rooms can be found starting on Floor 13. It has a single Deluxe Box that can have these items:
 * Icy Rock
 * Frozen Rock
 * Icy Dust
 * Reviver Seed
 * TM Trick Room

Boss
The boss of Crystal Ruins is a Mamoswine. It doesn't drop anything and has the moves, Ice Beam, Bulldoze, Dig, and Take Down. It is always snowing in this room. Before Fighting: After Defeating:
 * Mamoswine: Who are you to infiltrate this place!?
 * Mamoswine: I am the mighty Mamoswine, and I shall not let you pass! Prepare to be squashed like the insect you are!
 * Mamoswine: My queen...
 * Mamoswine: I'm sorry... that I couldn't protect you...
 * Mamoswine: I'm not strong enough to do anything...
 * Mamoswine: This is your fault... stomping into OUR castle... HER castle.
 * Mamoswine: You may have defeated me, but you won't defeat her. When she defeats you, I hope to never see you again, treading on our sacred home.
 * Mamoswine: She does not show mercy.

Crystal Castle Entrance
After the boss here is a midpoint between Crystal Ruins and Crystal Castle. There's a Kangaskhan statue to prepare before moving onto Crystal Castle.

Pokémon
''Pokémon in bold are recruitable. Please visit the Recruitable Pokémon page for more information.''

Dungeon Objectives
Mainly players come to reach Crystal Castle, try to obtain a Clear Silk, or fight Regice for the possibility of it dropping its Heart Slate. Dome Fossils can only be found here, and it's one of the earliest places to obtain a Ghost-type.

Trivia

 * This dungeon was created by Yatterman.
 * This dungeon was revamped alongside Crystal Castle on June 18th 2019 by Prismatic.
 * All NPCs at the entrance of the dungeon were named by players.
 * On January 2013 this dungeon, as well as Crystal Castle, was moved from Winden Forest Relic and placed in the overworld of Winden as its own dungeon
 * The story surrounding the creation of this dungeon as well as Crystal Castle is known as The Story of Winden.
 * Kabuto used to spawn as a recruitable in this dungeon, but was removed with the introduction of the Dome Fossil, which can now be found here. However post revamp, Kabuto was once again added as an unrecruitable spawn.
 * Regice spawns with multiple buffs placed on it.
 * Regice, unlike other Legendaries, has a lower chance of dropping a Heart Slate to offset how often it appears.