I had two dishes of iPS cells. In one of the dishes, I observed a mold-like colony which looks like a fuzzy ball with small protrusions all around and the iPS cells were dying. I discarded it and now the other dish had these vibrating small black dots (see attached image), many of them. The cells in this dish is also dying. I use pen-strep in the medium and so I don't think it is a cell-wall bacteria. Any idea what kind of contamination this is? Mycoplasma or mold or something else?