The Vault of Bones is a dungeon found in a forest near the Tree Fort. As the name suggests, it is filled with bones and is inhabited by sentient, possibly undead Skeletons (one notable skeleton has a big head and lost his arm in a pool of water), a hologram that looks like a frightening monster with a giant sword and shield, Goo Skulls, as well as an unnamed ostrich-like skeleton that resides in a locked box. The creature wants anyone who opens his box to "take his place," probably meaning that he will lock the person who has opened the box in the box, while he is free. He has a very raspy voice. He meets his demise when Flame Princess burns him. Also in the dungeon are various keys, two of which are a golden key and a key that looks like it is made out of demon blood like Finn's Demon Sword, which unlock a treasure chest containing a stone heart, or possibly a stone butt with eyes, hidden in the dungeon.