Allie Mystery Ducks are a variant of Mystery Ducks which appear in Mystery Duck Challenges.
- Allie Mystery Ducks are found in some Mystery Duck challenges. A new Mystery Duck challenge appears every 24 hours, but a different type of Mystery Duck will likely feature.
- When a player collects an Allie Mystery Duck and completes the challenge, it is added to the Mystery Duck counter. For every three Mystery Ducks collected, a new Duckie costume is unlocked.
- Allie Mystery Ducks require five drops of Steam to fill and collect. All other Fluids, except Water will kill Allie Mystery Ducks. If the Allie Mystery Duck is killed or if the level is completed without it being collected, the level fails.
- Once all Duckies that are unlocked with the Mystery Duck are unlocked, Mystery Duck challenges will no longer appear, thus, neither will the Allie Mystery Duck.
- While Full, the Allie Mystery Duck takes on the appearance of a full Allie Duck with a black, white and violet tuxedo, with a slightly slimmer. She wears a top hat with a violet ribbon.
- While Empty, the Allie Mystery Duck takes on the appearance of an empty Allie Duck with a tuxedo in various shades of pink. Her top hat remains the same.