The Bone Key is a drop from the Dungeon Guardian. The Dungeon Guardian will only appear if the player enters the Dungeon before defeating Skeletron, and this is perhaps the hardest pet to get, due to this bosses ability to kill the player instantly, and the long tedious battle to defeat it. When the Bone Key is used it summons a Baby Skeletron Head that will follow the player around.
Sometimes, when the player uses the Bone Key, it will summon two Baby Skeletron Heads.
- Added to the game.