Elek-Nawl, Void Dweller

If there are ten or more cards in exile, Elek-Nawl
has indestructible and hexproof.
{w}{u}{b}, Pay 3 life, {t}: You may cast a card from
exile, and you may spend mana as if it were mana
of any color to cast that spell. If that card was an instant, sorcery, or enchantment, Elek-Nawl gets
+4+4 until end of turn. If it was a creature or artifact, draw a card, then exile one card from
your hand.