This requires Nissa, Vastwood Seer. A good late game deck is required, as Nissa only transforms when you control at least seven lands. When ready, a good defense is required to keep Nissa, Sage Animist on the board at least four turns. Use her first ability to gain loyalty. When you reach at least 7, use Nissa's ultimate ability to untap six lands and they will become 6/6. Note: There is no expiration rule; if Nissa is put in the graveyard at this point, you will retain your 6/6 land-creature. Attack to do 6x6 damage to your enemy.