Black Bolt, Inhuman Voice

If you control more than four creatures, you may cast Black Bolt, Inhuman Voice without paying its mana cost.
{3}{b}, Discard a card from your hand: Target opponent must discard a card from their hand, then draw 1 card from their library and reveal it.
If the card they drew is a creature card, they lose life equal to the mana cost of that creature.
If it is a land card, they must exile it.