The Silver Sickle

When a Rift dies or a Godkin enters the battlefield
put a Ancient counter on The Silver Sickle.
{2},{t}, Sacrifice a permanent: Exile the top 7
cards of target players library, you may cast a spell
with mana value X or less where X is the number
of Ancient counters on The Silver Sickle. Put all
cards not cast this way into the graveyard.
{1},{t}: Add {c}{c}, put an Ancient counter on The Silver Sickle, if you spend this mana to cast a legendary spell untap The Silver Sickle.