So naturally, I had to show the duck in Crackdown to my wife, who is also nuts about duckies. Last night I spent half an hour trying to find another duck, then I went running through the streets of Pacific City, throwing a rubber duck at people. I also found out that the duck floats in water, and knocks people over. They ran away screaming when I threw a duck at them! The duck also squeaks when you throw it (such attention to detail!)
Unfortunately I lost the duckie when I got attacked. I threw the duck as a distraction, but the guy had grenades. I think the duckie blew up, or perhaps it went back to the water where it was safe.