How does the Cnidocyte of a Cnidarian Function? A cnidocyte, cnidoblast or nematocyte, is a type of venomous cell unique to the phylum Cnidaria (corals, sea anemones, hydrae, jellyfish, etc.).
Such cells are called stem cells. Stem cells are those undifferentiated cells which have the potential to become specialized to form a specific type of cell. For instance, mesenchymal stem cells are a type of stem cells which can differentiate into osteoblasts, chrondocytes, myocytes and adipocytes.
1 The first steps involve making more cells by simple cell division: one cell becomes two cells; two cells become four cells, etc.  Each cell of early development is undifferentiated; that is, it is not yet specialized to carry out a specific body function.