Swampy Ducks are the secondary objective that you have in Swampy's Story. To collect a duck, you must hit them five times with clean water. If it is hit with Poison Water, Toxic Ooze, or Mud, the duck will be destroyed and rendered uncollectable (they turn into a skull and makes a painful-sounding quack). There are three on each level of Swampy's Story. Also, on levels C1-5 and C2-10, you must fill Swampy Ducks instead of Cranky Ducks.