Carolina Gardening: Strange fungus on mulch, 0 by Clementine

Clementine wrote:
I am not sure that this is the right place to post this, but perhaps some of you in the Carolinas have seen this problem.

Yesterday afternoon, I saw a strange yellow area on the mulch (shredded bark), it was a bit darker than lemon and not sticky but sort of gooey. This morning, there are several patches of this stuff that now looks like light baked bread, sort of a little foamy. When you touch it, it is yellow inside, same yellow as yesterday. The mulch has been in place for about two months.

Any ideas as to what it is, where it might have come from, what damage it might do to plants, and how to get rid of it?

I'll post two pictures.