This is the first paragraph of an old very short story by Scott Siskind, which formed part of his sadly lapsed Consequentialism FAQ (but preserved on Wayback Machine, where you can see the rest:

In the deep jungles of Clamzoria across the Freptane Sea is a tall and snow-capped mountain. Within this mountain is a cave which is the lair of the dreaded Hrogmorph, Slayer of Men. Encased within the chest of Hrogmorph is a massive ruby called the Heartstone, a ruby with legendary magic powers. The stories say that whoever wears the Heartstone is immune from the moral law, and may commit any actions he desires without them being even the mildest of venial sins.