Yogg-saron, Hope's End

0: When Yogg-saron enters the battlefield, return all spells from your graveyard to your hand. His Loyalty is equal to the total spells.
-6: Cast all spells you are holding without paying their mana cost.
-10: Return all spells from your graveyard to your hand, as well as 4 spells from your opponent's graveyard. Your opponent discards a card.