The Crystal Cave in Forager’s Winter Biome contains a Boss Key trapped in ice. Your Fiery Pickaxe won’t melt it, and you can’t mine through. Getting this key requires solving a puzzle involving an item found deeper in the dungeon.
Step 1: Find the Ice Rod
Before you can get the Boss Key, you need to progress through the Crystal Cave. Take minecarts, clear doorways, and explore until you find a Blue Chest.
The Blue Chest contains the Ice Rod. You’ll keep this item after leaving the cave – it’s a permanent tool.
Step 2: Return to the Boss Key Room
With the Ice Rod in your inventory, go back to the room where the Boss Key is trapped in ice. You’ll notice a Brazier (fire torch) on the opposite side of the room from the key.
Step 3: Freeze the Brazier
Use the Ice Rod on the Brazier to freeze it. This causes a laser beam to shine from the frozen Brazier onto the ice encasing the Boss Key, melting it.
Once the ice melts, walk over and pick up the Boss Key.
Bonus: The 3 Frozen Chests
The same Ice Rod technique works on the 3 frozen Small Chests in a nearby room. Use the Ice Rod on Braziers to redirect laser beams and melt the ice on each chest. Check out our Crystal Cave Chests guide for the full solution.
What the Boss Key Opens
The Boss Key unlocks the door to the Crystal Cave boss fight. Defeating the boss rewards you with valuable loot and progresses you toward completing the dungeon’s Feat.
