Nithoskiz, Voidfire Tyrant

Flying, Supremacy 5 (When you cast this creature
you may pay an additional {5}, if you do, this creature
enters the battlefield with 5 +1/+1 counters on it.)
{3}{b}{r}: Choose a number. Destroy all artifacts
and creatures with converted mana cost equal
to that number. Then target player reveals their
hand and discards all nonland cards with
converted mana cost equal to the number.