Kansas snappers can be every bit of 20+ lbs and 18 inch wide shells. I know I moved one out of an intersection in my folks neighborhood with a scoop shovel. It was in the middle of the intersection turning itself to watch cars go by and there were quite a few motorists trying to get it to crawl away which it had no intention of doing. I tell you this thing was a monster and didnt appreciate my efforts to move it with the shovel.
Since it was coming from a wooded area, I suspect it had just laid eggs and was heading back....