Serenity

Ship 4. (You may attach up to 4 creatures to Serenity. They gain Flying and together have a base power and toughness of 4/4. Any damage done to attached creatures is done to Serenity's toughness of 4. If Serenity would be placed in the graveyard shuffle it into your library. All creatures attached are returned to the battlefield tapped).
When Serenity leaves the battlefield draw 3 cards.