There doesn't seem to be anything unusual about the stone itself, but the cyclopes believe it to be a great tr

There doesn't seem to be anything unusual about the stone itself, but the cyclopes believe it to be a great treasure... It seems reminiscent of an enchantment spell. The ancient builders of this necropolis must have used the obelisk to create an inconspicuous but deadly trap. Any cyclops who got close enough would stay here, entranced by the obelisk, until they fell dead of exhaustion or starvation. Fortunately for you, spells like this typically can't target all sentient creatures, but rather need to be keyed to target a specific kind of creature — for instance, cyclopes.