Krystal Field

As an additional cost to cast this spell, sacrifice a
land.You must control Sky Krystal/Sky Guardian
card; if you don't, destroy this card.
{t}: Add one mana of any color.
{w},{t}: Search your library for a Sky Krystal card
with converted mana cost 2 or less, reveal that
card, and put it into your hand. Then shuffle
your library.
{c},{t}: Flash, Untap target legendary permanent.