Destroy target land. Search your library for a basic land card and put that card onto the battlefield tapped. Then shuffle your library.
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.
1/24/2013 If the target land is an illegal target when Frenzied Tilling tries to resolve, the spell won’t resolve and none of its effects will happen. You won’t search your library for a basic land card.