Knowledge Exploitation [Morningtide]

Set: Morningtide Type: Tribal Sorcery — Rogue Rare Cost: {5}{U}{U} Prowl {3}{U} (You may cast this for its prowl cost if you dealt combat damage to a player this turn with a Rogue.) Search target opponent's library for an instant or sorcery card. You may cast that card without paying its mana cost. Then that player shuffles their library.