Hi.

This happened in a store chainbound event I took part in, and no one was really sure the best way to resolve this ruling.

My opponent sacrifices Lifeward during their turn.

On my turn I play Wild Wormhole and the card thats played from the top of my deck is a creature.

What happens to the creature card that you cant play? Would it be discarded, or would it just go back on top of your deck?

Thanks for any help or clarifcations.

Any card which does not meet the requirements goes back to it's original location. Just as if WW had played an upgrade with no creatures on board the card will go back to the top of the deck.