Case of the Uneaten Feast: Murders at Karlov Manor

Whenever a creature enters the battlefield under your control, you gain 1 life. To solve — You've gained 5 or more life this turn. (If unsolved, solve at the beginning of your end step.) Solved — Sacrifice this Case: Creature cards in your graveyard gain "You may cast this card from your graveyard" until end of turn.