Known to only a few to be the Willful Curse, this small colorful stone can be used by any willing creature who is aware of what the stone can do. The stone is only able to be used if somebody within the same plane of existence has attuned to it. In order to use it, a creature must hold the stone in their hand and concentrate on it. After a moment, if the stone is functional, the stone will light up briefly and the curse will activate. The curse can last anywhere from ten seconds to a week. The dungeon master chooses the curse. The creature can use this stone as many times as they choose. 

Notes: creature capable of casting spells