Volleyballs or Something Else?

One day these things were not on the trails, the next day they were!  At first, I thought they were volleyballs and apparently someone else thought the same thing.  Those two holes look like someone poked their fingers in it to see what it was.  Apparently, they are some type of fungi.  Saw them in two different places:  Winton Woods and Fernald Preserve.  I thought they were very interesting. Had never seen anything like them before.

 I liked the colors in the next two photos.

More volleyball sized fungi.

Along the trail at Fernald Preserve.