Celestial Harbor

Limbo {w}{u} (You may exile this card from your
hand for its limbo cost at any time. You may return it from exile to your hand anytime for its limbo cost.)
Whenever you would exile this card from your hand, you may reveal it instead (it remains revealed until it changes zones). If you do, exile a creature you control. Return those cards to the battlefield when Celestial Harbor changes zones.
Creatures you control get +1/+1.