Knowledge Exploitation | Magic: The Gathering
Formats Knowledge Exploitation is Legal in
Official Oracle Text for Knowledge Exploitation
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 his or her library.
Official Rulings for Knowledge Exploitation
4/1/2008 : If you can't find an instant or sorcery card that can be legally cast, or choose not to find one, skip that part of the effect. Then the opponent shuffles his or her library.