Demon Door

Scattered across the world and incredibly rare are Demon Doors, stone carved faces on solid stone doors so old that none living remember their creators, they've intrigued many travelers. Enchanted by some ancient magic, these are sentient slabs of stone who will ask a riddle to those who manage to find it. Answer the riddle correctly, and they will open their door for you - what lies inside? Trap or treasure? None can tell.