If the ability triggers and the Urn isn't sacrificed (because it left the battlefield or changed controllers, for example), the exiled cards won't be returned to the battlefield
You just have to control the Aura or Equipment youre targeting as well as the creature youre targeting.
MTGNexus homepage MTGNexus creator options Pros: Layouts for every card frame you can think of Save cards as sets, cycles, or individually Great forum for discussing card creation topics Collection tracker tool Cons: Requires sign up How Do I Print My Own Proxy
Geralf, the Fleshwright creates a Zombie token when you cast any spell that's not your first spell that turn, Open the Graves creates a Zombie token when a nontoken creatures you control dies, and Cryptbreaker makes a Zombie token by discarding a card and tapping itself
Maybe you are playing Otters and really need to find Enduring Vitality and Valley Floodcaller, and you likely win the game if you do