A nkisi is a power or spirit from the invisible world of the dead, who may also reside in a statue. Almost every adult man or woman possesses a nkisi na moganga as a personal protector. These are generally small wooden figures in human form, but receptacles in the form of shells or gourds are also found. The figures are fairly small, up to around 20 cm, and have a friendly facial expression. Their appearance is neither male nor female and their surface often feels smooth and shiny, because the owner tries to keep the power figure vigilant by constantly rubbing it. A nkisi na moganga often stands on the family altar in the home.<Br>The ritual specialist or nganga brings a nkisi to life by attaching an empowering substance (bilongo) to it. Bilongo entices a spirit to come down from the heavens and to take up residence in the figure. If these magical substances fall out of the nkisi, it loses its powers.