Ik'Nzyl, It That Begets Fear

If colored mana was used to cast Ik'Nzyl, It That Begets Fear, you lose half your life total (rounded up).
Flying, annihilator 2
At the end of each turn, each opponent exiles a card from their graveyard and loses life equal to that card's converted mana cost. If there are no cards in that player's graveyard, they exile the top card of their library instead.