The Kongo nkissi were objects for white positive magic or black negative magic. For this reason, they were feared by all, and the nganga who possessed them was someone whom members of the community would have avoided upsetting when appealing for his power during a consultation. (Image and text taken from http://www.christies.com/lotfinder/sculptures-statues-figures/statuette-kongo-nkisi-kongo-power-figure-nkisi-5686630-details.aspx )