I have no idea what species this little guy is. He was also about the size of a quarter, but doesn’t match any of the photos in my Frogs & Toads of North Carolina website of choice closely enough to make an ID for sure. (very small bronze frog? Maybe?) He was exactly the color of the dirt, and I would never have spotted him if he hadn’t moved.
Eventually I just mulched around him, leaving a square inch unmulched so as not to trouble him. He pressed himself into the dirt and glared at me.
Any herpetologists in the audience who can name him, I’d be delighted to know what he is!