The Skeleton Key is an item featured in the console version of Skylanders: Spyro's Adventure and the Nintendo 3DS version of Skylanders: Swap Force. In Spyro's Adventure, it is used to unlock the gate to the Creepy Citadel and is held within Cadaverous Crypt. The Skylanders venture to the crypt with T-Bone the Skeleton to claim the key in order to find the Eternal Undead Source, and T-Bone comically attaches his own head to the key.
