More angles here:
I think it might be a green-spored parasol which is poisonous, but it's hard to tell at this stage. Was hoping it's something edible because there's lots of them and they're massive.
Looks like a False Parasol in my eyes, though remote ID is a bit hard of course.
Why? The edible Parasol is usually brown with a dark brown underside, has flakes at the cap and stem, and the ring is detachable.
But don't trust my impression alone please, I'm no ID expert!
Can you move the ring around the stem up and down or is it grown on?
But may very well be a false parasol aka vomiter, considering the "yard" location.
The ring around the stem is firmly attached.
Don't verify based on the ring. Can't see, but a snake skin pattern on the stem is a good indicator of an edible. Never trust an internet ID though. Find a knowledgeable person who can see, feel and smell it first hand.
Yeah I don't plan to risk it. I also rubbed the gills on a paper towel and it stained it green, so I'm pretty sure at this point that it's a green-spored parasol / vomiter.
Looks like a Macrolepiota dolichaula.