The Mystery Duck is one of the three variations of ducks used in the Mystery Duck's Story.
- If not a Mega Duck or a bunch of Ducklings, the teleporting and levitating Mystery Duck will take the spotlight and challenge the player on a Swampy level.
- The player is required to collect the Mystery Duck before moving onto the next level. In addition, a certain number of Mystery Ducks must be collected in order to unlock more chapters in the Mystery Duck's Story. Completing one level counts as one, regardless of whether it contains a Mystery Duck, a Mega Duck or Ducklings. Alternatively, the player can use the Locksmith Duck.
- In some levels, it teleports between a number of duck spaces (examples are First Dig and They've Got Chemistry). In others, it clips through dirt and rocks, and either stops when its at a certain position or leaves the level (example is Going Down?).
- The Mystery Duck requires five drops of Water to be collected. All other fluids, except Steam will kill the duck.
- The Mystery Duck has a similar shape to a Swampy Duck but the Duck's top eyelid is down. The Duck wears a large top hat, and a tuxedo.
- While full, the Duck's skin is Yellow. The Hat and Tuxedo are black with red and white trims.
- While empty, all but the hat is desaturated.
|Mystery Duck is Collected|
|Mystery Duck is Filled|
|Mystery Duck is Killed|
- A total of 200 Mystery Ducks can be found in the Mystery Duck's Story.
- If the Mystery Duck is killed by either an explosion or by some hazardous liquid, he will turn into a skull wearing his top hat to the left instead of the right and makes a painful-sounding quack.
- The Mystery Duck can break through icicles, as seen in Spa Treatment.