Pyramid of Gambling (3.5e Equipment)
From D&D Wiki
 Pyramid of Gambling
This pyramid-shaped pendant bears the shape of an eye. When commanded, the pendant will shoot a small ray of energy and brand the target and yourself with an instant mark of justice. You may choose the curse of the Mark at the time of each casting, but the act is already chosen. The target and you must play a game of your choice. The loser dies, and its soul is trapped in the pendant.
The pyramid cannot be taken off once equipped. If the wearer loses the game and dies, the pendant will teleport itself onto the winner. If you don't challenge someone to a game every week, the pendant will randomly choose a target for you at the earliest convenience.
You gain a +5 on all skill checks that apply to the games.
When active, your alignment is changed to the alignment of the majority in the pyramid. You are also able to use the feeblemind spell anytime at will. You can choose when the Pyramid is active as long as you willingly start a game with another creature every week.