The Arbiter

Defender, Flying, Protection from everything
When The Arbiter enters the battlefield, exile all
other permanents you control, your hand, your graveyard, and your library.
You do not lose the game as a result of drawing
from an empty library.
Whenever an opponent casts a spell, you gain
control of that spell, then choose a spell with the
same converted mana cost from among the cards
you own in exile. That opponent casts that spell without paying its mana cost.