It looks like a brain coral. It is about a foot in diameter. It is Dry to the touch but still a bit soft. I live in Prince Edward Island in Canada.
I've got to say that looks an awful lot like a brain coral with moss growing on it. I know of no mushrooms that look nearly as similar to brain coral, and I don't think any fungal fruiting body would last long enough on the ground to grow moss like that.
I think someone went to Florida or the Bahamas many years ago, and brought back a souvenir. We've got some sitting in our woods from family trips we took 30 years ago.
You could rule that out fairly quickly, though, by poking it. Is it solid or yielding? If it gives a bit when poked, you can rule out the coral.
Calvatia craniiformis (Brain puffball)