Bane of Revilo

Flying
Each opponent can't draw more than one card
and cast more than one spell each turn.
At the beginning of your turn, target opponent chooses a number then reveals the top card of their library, if the converted mana cost of the card is equal to the chosen number, until your next turn opponents may cast spells normally
"Aww that's a mean card..."
~Revilo, Master of the Cheerios