Spire

Cannot attack or block. Costs {3} less to cast
if you control a building named Lair or Hive.
{t} : Add {1} to your mana pool. Spend to cast creature spells that have Flying.
{3}, {t}, Exert : Return target non-legendary creature with flying from your graveyard to
your hand.
{3}, {t} : Evolve Greater Spire