Nazuki, Predator

You may pay {g}{g}{g}{g}{g} rather than pay
Nazuki's mana cost as long as your life total is
equal to or above your starting life total.
Flying, trample, indestructible.
Whenever Nazuki becomes blocked, you may
have it deal damage equal to its power to
defending player. If you do, it assigns no combat
damage this turn.