mushroom

I have to agree that it doesn't look just like Naemateloma (Hypholoma); the gills aren't really dark enough to indicate a brown spore color, although the rest of it is right. Will try to think of something better.

It's not Naemateloma capnoides. Unfortunately I can't help you with a better name for it...

Should have a dark brown spore print to be Naemateloma

Sounds like your dog is a good mushroom spotter! This is very pretty.