These little fellows have shown up in our front yard. The one above is about eight inches across. I didn't quite get the keys in the bottom of the picture to show scale.
The large one below is about a foot across, its smaller friends are about three inches across.
Fliegenpilz is the German name for these, or a similar European cousin. They are often used as inspiration for Räuchermann or Räucherpilz, in which pieces of incense are burned so that smoke comes out the "chimney." We prefer the ones that look like little cottages for elves or brownies, rather than faces scroll down about halfway, and on toward the bottom, on that web page to see some examples. And maybe I'll find some pictures of ours to post soon.