Part the Clouds

Delve (Each card you exile from your graveyard
while casting this spell pays for {1}.)
Exile all creatures your opponents control, then
return them to the battlefield at the beginning of
your next upkeep.
Rebound (If you cast this spell from your hand, exile
it as it resolves. At the beginning of your next upkeep,
you may cast this card from exile without paying its
mana cost.)