Puffball

I will second hookgv on his suggestion for an id. This is a puffball mushroom.
There are a few different types of puffballs, this size, and the giant puffball.
I get giant puffballs in my yard in the fall. Some are the size of beach balls.
Puff ball mushrooms are edible, and have a wonderfully woodie flavor to them.
They should only be eaten when they are fully milky white inside. I hope this helps you and gives you a bit of information on this delicious mushroom