Yes-Man, Key to the Kingdom

As you cast this spell, you may pay {b}{w}{u}. If you
do, gain control of all nonland permanents your
opponents control with mana value equal to or
less than the number of treasure tokens you
control. You become the monarch.
If you are the monarch, whenever you draw your
second card each turn, you may destroy target
creature you don't control with mana value equal
to or less than the number of treasure tokens you
control.