Where we've had trees cut down to improve light levels, we get an annual crop of these pretty little Ink Cap type fungi.
They appear almost like magic, overnight, usually after heavy rain has soaked the ground, and on the area where the roots of the felled tree are still in the ground but gradually rotting down. Fungi help this process, and do no harm. Indeed many millions of fungi are found in healthy garden soil and are essential for plant growth.. Although the Inkcaps in my garden aren't edible, some inkcaps, notably the Shaggy Ink Cap, or Lawyers Wig, which you can see everywhere in the autumn, are edible. I've tried Shaggy Ink Caps fried with a bit of bacon, and found them ok but nothing special, and not so good as many other wild fungi, such as Parasols, which are delicious.
Incidentally, Inkcaps are so called because all members of the family soon deliquesce, as it's called, into a black inky mess, soon after they're picked, and the resultant liquid was used as a writing ink.
It goes without saying of course, that you should never consume any fungi you pick unless you are absolutely certain about what it is. Amanita Phalloides or the Death Cap mushroom is said to be the cause of more than 90% of European fatal mushroom poisonings, and to the untrained eye can look remarkably like a tasty supper. So take an expert, do a course, and take great care.