When Captain Jack enters the battlefield and at the beginning of your upkeep, exile the top card of your library. If the total mana value of cards exiled with Captain Jack is greater than 21, Captain Jack deals damage equal to its power to you.

Captain Jack's power is equal to the total converted mana cost of cards exiled with it.

{T}, Sacrifice Captain Jack: Captain Jack deals damage to you equal to 21 minus its power. Put all cards exiled with Captain Jack into your hand.