Mississippi Queen

All Aboard! - You may tap any number of creatures you control to Crew this card, then this card becomes a creature in addition to its other types. When Crewed, this card's Power becomes equal to the total Power of creatures Crewing it. Creatures tapped this way stay tapped for as long as this card is Crewed. You may Crew or Uncrew at any time.

{t}{x}: {x} is this card's Power. Deal X damage to target creature or player.