This whatever-it-is appeared last week in a damp area in our yard. It looked like black mold on the ground. Upon further inspection, it appears to be a mass of tiny, living creatures. They are about the size of a pinhead. They appear dull black, but if you use a flash camera they have a whiteness to them. They're extremely tiny (like the period on size 12 type)and cluster together so they look like mold. It rained last night, and some of them moved up onto the sidewalk and are floating on top of puddles (the ones in this photo, for instance). I'll submit another picture from a distance to show how they appear when walking up the sidewalk. Any ideas? I'm stumped.