The Lost City of Eldrath

This permanent cannot be sacrificed, ward {w}{u}{b}{r}{g}

At the beginning of your upkeep, add X mana in any combination of colors, where X is the number of creatures in all graveyards. This mana can only be used to cast creature spells or activate creature abilities.

Whenever you cast a creature spell that has {w}{u}{b}{r}{g} in its mana cost, draw five cards and transform The Lost City of Eldrath into an X/X Legendary Zombie City with "Hexproof" and "Nonbasic landwalk" until end of turn, where X i