Chaos Hydra

Cascade the Bank twice. (When you cast this spell,
exile cards from the top of the bank until you exile a
card that costs less. You may play it without paying
its mana cost. Put the exiled cards on the bottom of the
bank.)
Chaos Hydra enters the battlefield with +1/+1 counters on equal to the total converted mana
cost of the spells cast with the cascade ability
on this card.