To Turn to Ashes

Exile any number of cards in your hand. Deal X damage to any number of targets, where X is their converted mana cost. For each creature you destroy with this, put a +1/+1 counter on target creature.
"Pitch black clouds shadow the burning sun, But I
won't let these vultures think that they have won
I'll be the last one standing when the end's begun"
—He Who Ruined It All