Adept of Nyx

Whenever Adept of Nyx attacks, put a card you
own in exile into your graveyard.
Creature cards in your graveyard have encore.
The encore cost is equal to their mana cost.
(Exile this card from your graveyard: 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.)