What is this Fungus?

What is this??? This icky fungus is growing around the edges of some of the beds. The bottom, on the soil, is mushy, and the top of it is kind of leathery. It's starting on the edges of the beds that were done first, so I'm wondering if in time it will show up around the others. So far it's just on the edges, underneath the hay mulch that is there to keep the moisture in. It's been very wet--Perhaps if we remove the mulch and expose it to the sun the fungus won't grow? I've looked around a bi ...