Hi Mrs Falce, It dosn’t sound like mold. What I think it sounds like is old split drinks like Coke Cola or coffee which had alot of sugar in it. Its soaked through the carpet and the sugar has now made the floor become very sticky under the carpet. First try washing the area with warm soapy water then try of with some towels. It won’t get rid of the stains but it will get rid of the thick sticky dirt. regards Noelene