Summon the Ancients

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Put a 9/9 blue Giant creature token with protection from green onto the battlefield under your control. Put a 9/9 green Giant creature token with protection from blue onto the battlefield under target opponent's control.
The primal fury of forgotten aeons, unleashed.