Galactus, Eater-of-Worlds

+2: Until your next turn, whenever a creature deals combat damage to Galactus, Eater-of-Worlds, destroy that creature.
-3: Put a legendary 5/5 colorless avatar creature token named Herald of Galactus onto the battlefield. That token has defender, and flying.
-10: Destroy all lands target player controls. Add X mana of any color to your mana pool, where X is the number of lands destroyed this way.