I'd seen this duck asleep before but with it standing up and stretching out, I could see the unusual coloration better. I still think this is a hybrid between a mallard and a domestic Muscovy. I've only seen that kind of iridescent feathers on muscovies. Never of domestic mallards. Cool looking duck. Check out the feet, more like Muscovy than mallard.
Mallard x Muscovy Duck (Anas platyrhynchos × cairina moschata)