Pattern of Rebirth | Magic: The Gathering
Formats Pattern of Rebirth is Legal in
Official Oracle Text for Pattern of Rebirth
When enchanted creature dies, that creature's controller may search his or her library for a creature card and put that card onto the battlefield. If that player does, he or she shuffles his or her library.
Official Rulings for Pattern of Rebirth
10/4/2004 : Because the "search" requires you to find a card with certain characteristics, you don't have to find the card if you don't want to.