I admit it. I rotated the photo in this pop quiz (right) just to make it more difficult to identify what it was.
I found this fellow as he is shown above. He didn’t move when I approached. I thought he was dead because he was so exposed. After I took a few pictures of him, I tapped him with my toe and he quickly returned to the pond.
I think he was beginning to moult. In the larger image, his eyes are cloudy and bluish. I couldn’t find anything online about how the eyes look before moulting, but I know snakes’ eyes become cloudy before they shed their skin. Crayfish moult 6-10 times during their first year and 3-5 times their second. This guy was really large so he might be on his third year although it’s rare for them to live that long.