It is rumored to be a bone of the first stalfos plated in memento mori gold.
Must be held in a free hand to use and maintain effect. As a standard action an undead whitin view must make a Will save with DC 10+1/2 HD+highest stat mod or be dominated. An undead that saves cannot be targeted again for 24 hours but instead they suffer a -6 penalty to AC and a -3 penalty to saves. Only one undead can be affected at a time, be it domination or penalty, activating the gold bone again (or it no longer be held in an hand) ends the previous effect.
You sense more hidden power in it but cannot unlock it yet.