NH Nut Identification Situation

We live in an age in which there are apps that can identify every natural living thing b snapping a simple photo of it. I choose the old school way.

And THAT is by asking you Shark listeners just what is this?

It is most certainly a nut, yet unlike any nut that I've seen. Unfortunately, it's way too early to tell what it's going to look like when after it ripens this fall. I've smashed these open and it really only looks like a seed pod at this point.

When I used to live at the corner of Sixth and Whittier here in Dover, there was (and still is) a beautiful hickory nut tree. Every October after a windstorm you could walk around the yard with a bucket and then feast away for as long as you felt like cracking.

So, I know for a fact this isn't a hickory nut tree.

Here is what the leaves look like and in the background you can see trunk and bark.

The leaves do look like that of a horse-chestnut tree but, I grew up just one block away from a gigantic one, so I know it's not that either.

It's also not an American Chestnut tree. They're very rare and are 'critically endangered'.

My Uncle Doug actually found one at an undisclosed location up in New Durham and I know that the husks of the nut are really spiny and brown, not smooth and green like this one.

So, it's up to you Shark Nation! What kind of a nut did I just find?