Alhammaret, High Arbiter [mana]5UU[/mana]
Legendary Creature - Sphinx
Rare
Flying
As Alhammaret, High Arbiter enters the battlefield, each opponent reveals his or her hand. You choose the name of a nonland card revealed this way.
Your opponent can't cast spells with the chosen name (as long as this creature is on the battlefield).
5/5