I kind of want to run this in Dark Sun. Lots of creepy old war relics are in that world--I can picture the players awakening a mummy, bone golem or some other horror that follows them slowly, inexorably, programmed by a long forgotten god-king to kill whomsoever gets on his bad side. Except he's long dead--and thus, so is the "off" switch for this thing.
Would be fun to give it sand-walk teleportation or something. The party thinks they've escaped, but they forgot that patch of silt in the corner... And suddenly there's a cracking sound.
It's the rearmost party member's neck being slapped.