Summa-Verminoth

Flying

Summa-Verminoth's power and toughness are each equal to the number of cards in your opponents’ graveyards.

Whenever you cast a spell, each opponent reveals cards from the top of their library until they reveal a land card, then puts those cards into their graveyard. You may cast a spell without paying its mana cost from amongst cards put into the graveyard this way. If that spell is a permanent card, it enters with a finality counter on it. If it's a nonpermanent spell, exile it as it resol