From what I can tell from the photo I'd say it is just a first year drake mallard that has mostly just colored out on the head. Hard to tell but the bill, feet and what I can see of the wing it looks pure mallard. If the bill was less yellow I might have said old hen with a hormone problem but the bill hasn't been changed on the ones I've seen.
Speaking of hybrids I recently saw a photo of a dogs first waterfowl retrieves. One was a Bluewing the other was clearly a Mallard x Pintail. How cool would that be. I hope he knew what it was but I fear he thought is was just a funny looking mallard.
Tim