Murders at Karlov Manor Foil: Case of the Burning Masks

When this Case enters the battlefield, it deals 3 damage to target creature an opponent controls.
To solve - Three or more sources you controlled dealt damage this turn. (If unsolved, solve at the beginning of your end step.)
Solved - Sacrifice this Case: Exile the top three cards of your library. Choose one of them. You may play that card this turn.