Swashbuckler Extraordinaire is a uncommon Creature — Dragon Rogue Warrior card from Alchemy Horizons: Baldur's Gate (HBG), collector number 190.
When this creature enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.") Whenever you attack, you may sacrifice one or more Treasures. When you do, up to that many target creatures gain double strike until end of turn.