There is a mold that *looks* sponge-like that is growing in various spots on my mulch. It seems to appear very quickly (it seems like overnight but that's probably because I'm not observing daily), and I notice the following life cycle:

 1. The mold is a moderately rich orange color that looks neither dry nor moist.
 2. The mold seems to rise (like baking bread) and expand in diameter and turn a more pale orange (like in the first image below)
 3. The mold "pops open" and exposes black spores.

I can poke the mold at steps #1 or #2 above to make it "pop" and have the black spore exposed.

The mulch was made from some trees that I had cut down on my property, one fir and one white birch.

I am wondering a) what is this mold and b) is it benign or could it be harmful to plants?

[![Mold in mid-stage life cycle][1]][1]
[![Mold in end-stage life cycle][2]][2]

  [1]: https://i.sstatic.net/ZnXwc.jpg
  [2]: https://i.sstatic.net/0OXpT.jpg