The duck shark is a very friendly creature that appears in various puzzles. It can help the player in various ways, such as being used as a platform while it crosses water, helping a player reach a ledge they can't quite reach, and launching a player forwards to make long jumps.
This creature is rather bizarre in design, as it resembles a plump, bright green duck-like creature with symbols for eyes. It is referred to as a shark in the opening cutscene of the story mode and is even shown shapeshifting into a shark in the ending sequence.
One of the special star heads that can be unlocked is a Duck-Shark.