Goku, the Unifier

Legendary Creatures you control get +X/+X,
where X is the number of legendary creatures you control.
Whenever you cast a legendary spell from your
hand, exile cards from the top of your library
until you exile a legendary non land card with
lesser mana value. You may cast that card without
paying its mana cost. put the rest on the bottom
of your library in a random order.