I agree with your second sentence. My guess is that it will be some small mushroom forming species and that you've photographed it soon after the mushroom primordia have started forming. If you see this again it could be worth another photo (or more) to show the development over time. I did this with a piece of wood in my yard (see Mycena 'clarkeana group'). Of course that was easy, just 5 seconds out the back door, so I could check it often very easily.