Ice Crown

The Ice Crown is a summoning item used to call forth Cryo Queen. It is restricted to the Deep Snow Caves, and cannot be used outside that biome.

Because it is a boss-summoning item, its main purpose is to trigger the Cryo Queen encounter when the player is ready. This makes it part of the progression around cold-region exploration and boss hunting. If you are carrying it, make sure you are already in the Deep Snow Caves before attempting to use it, since the item only functions there.