Zwarte Madam is a witch from Flemish or Dutch folk tales.
Her characteristics tend to vary, although she always seems to be in service of the devil, collecting the souls of mortals.
As a consequence, she can be warded off by the use of Christian symbols or the mention of a sacred name.
Often she can be seen travelling silently alongside wanderers destined for hell. Zwarte means Black, madam is to be read as a polite dialectical title for a middle aged woman, in a certain sense like lady.