Hyas, Son of the Titans

Giant creatures in your graveyard gain encore. The encore cost is equal to the card's mana value plus exiling cards from your graveyard equal to the number of opponents you have. (Exile the creature card and pay its encore cost: For each opponent, create a token copy that attacks that opponent this turn if able. They gain haste. Sacrifice them at the beginning of the next end step. Activate only as a sorcery.)