Pattern of Rebirth

Oracle Text

Enchant creature

When enchanted creature dies, that creature's controller may search their library for a creature card and put that card onto the battlefield. If that player does, they shuffle their library.

Card Rulings

10/4/2004 Searching for a creature card is optional.
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.