Unwanted growth on the roof

There was something on our roof that puzzled me because something was falling on the ground. When I climbed the roof, I discovered that there are 2 mushroom growing by the side. The mushroom grew on the wood flashing of the rood. It is not really unwanted since it is not a pest although the mushroom can somehow ruin the wood.

As of now, I am observing the mushroom on what it would do. Maybe it can have spores and bring  more mushroom sprouts. But none of that for 2 months now based on my observation. Maybe I have to wait for the rainy season before something remarkable would happen.