The Clever Magician — Unknown Event #RU04a

Rule Zero — Whenever this creature enters the battlefield, and before the game begins if this creature is your commander, you may propose a new rule that is contained to this game of Magic. If all players in the game agree to it, that rule becomes true for this game. If one or more players decline, instead you scry 2. (If this is your commander, scry after keeping your hand.)