[Peter Finke]

I am not sure whether this strange structure is funghus; I had it myself several times. I do not know under which circumstances they occur, however. At any case, it is not dangerous at all.
But the other, more important thing is that small bubble-nest: At least on one picture is the bundle ob bubbles to be seen. Very rarely Paros build a small bubble nest within a thick structure of algae or higher plants, for instance Java moss. I had it myself twice with P. paludicola and P. linkei, too.