Reorder your graveyard at random. An opponent chooses a card at random in your graveyard. If it's a creature card, put it onto the battlefield. Otherwise, exile it.
When there are no creatures on the battlefield, sacrifice Task Mage Assembly. {2}: Task Mage Assembly deals 1 damage to target creature. Any player may activate this ability but only as a sorcery.
Whenever a nontoken creature enters, its controller creates a token that's a copy of that creature. Whenever a nontoken creature leaves the battlefield, exile all tokens with the same name as that creature. When Dual Nature leaves the battlefield, exile all tokens created with Dual Nature.
Each player creates a green Elephant creature token. Those creatures have "This creature's power and toughness are each equal to the number of creature cards in its controller's graveyard."