This is pretty wild I have to say. Saw a friend recently that told me a pretty crazy story from a few years back, I was out of town at the time which is why I found out only today.
My friend and his buddy would hike this remote stretch of woods in our town going metal detecting, really no one goes where they were because there arent real trails there. They still go all the time, they find all sorts of cool shit in odd areas, its not a hobby for me with my lack of patience... anyway I digress.
Well one day they are back there and they see that someone was starting to dig a hole, basically in the middle of nowhere, there are no houses for over a mile and its not that close to the road. Well they go back there more and more and they see the hole is getting bigger, the footprint was like 5 feet by 4 feet he said and it was starting to get deep. Of course its really odd that someone would go back to a remote area multiple times to dig a hole, so my friends friend buys a trail cam, to see who is doing the digging. He sets it up and after a week or so it picks someone up. Picture below: