What if there are *multiple* proper keys, each with a different effect?Bone Key of the Sepulchral Oracle: the skull answers three questions that are put to it. One of its answers will be a lie.Incendiary Key of Iconoclastic Brotherhood: upon inserting and turning this key the skull begins ticking...after 30 ticks it explodes and engulfs the area in caustic flame.Necromantic Key of the Undying Warrior: upon turning the key the skull sprouts a full skeleton. Once fully formed the skeleton will obey any commands given to it by its completer.
Turning the key opens a gateway to some strange dungeon.
Oh thank you! One of my players has been carrying around a key she found in a dungeon way back in session 2 and trying it in every lock she finds. Still hasn't opened anything but now I have an idea of just what it'll do...
I think a skull lock obviously requires a skeleton key. ;)
What if the skull does nothing? However, when the person with that skull was /alive/ you could insert a special key into their forehead, turn it and unlock some kind of powerful divination. They would begin babbling incoherently at first, then enter fugue state where they would answer questions with a voice not their own.