It's the largest type of mushroom where I live! Giant Puffball Mushroom! 

Because the mycorrhizae? If so that is VERY interesting. I look forward to your reply!

Ahahahah We have them up here in Canada ON. We call them puffshrooms ahah. My Grandfather had one under his gazebo and it was actually lifting it off the bricks, they can be pretty strong.

great eating

thats some good eating if your able to