True.
In the traditional religious practices of the Kongo people of Central Africa, a nkisi Mangaaka is a power object believed to provide protection, healing, and other benefits. To activate the spiritual energy within the nkisi, ritual specialists known as nganga would drive metal objects such as nails, knives, or blades into it. This practice, known as materialization, was used to imbue the nkisi with the power of the spirits and make it a potent tool for the nganga to use in various practices such as healing and divination.