When Nyla enters, exile up to one target creature card from your graveyard. If you do, you lose X life and create X Clue tokens, where X is that card’s mana value. (A Clue token is an artifact with “{2}, Sacrifice this token: Draw a card.”)
At the beginning of your end step, if you control no Clues, return target card exiled with Nyla to its owner’s hand.