Patchouli Knowledge

{b}{x}: Deal X damage to target creature
{u}{u}{u}: Exile up to 3 instant or sorcery cards from your hand. When Patchouli Knowledge attacks, you may choose to prevent all combat damage from Patchouli Knowledge this turn. If you do, you may cast one of the exiled cards without paying its mana cost.
{w}{w}, Sacrifice a land: Search your library for a land card and put it onto the battlefield. Shuffle your library.