Wondrous Item (dice set) , Rare (unique)
This set of dice was created by the druid mathematician Bent Tokar. They were a mathematical experiment to see if observation of a result could have an effect on the result, thereby possibly changing the objective reality of the die roll. When the dice are rolled the "result" can be seen by the wielder for a split second or two before anyone else. The wielder can then choose to accept the objective roll, or force their will upon the dice, changing them to a different subjective roll.
(anyone attuned to the dice by claiming them, can roll with advantage, keeping either the first or the second roll as the result.)