Sow Chaos

Buyback {3} (You may pay an additional {3} as you
cast this spell. If you do, put this card into your hand
as it resolves.)
Cascade, cascade (When you cast this spell, exile
cards from the top of your library until you exile a
nonland card that costs less. You may cast it without
paying its mana cost. Put the exiled cards on the
bottom of your library in a random order. Then do it
again.)