John Montgomery discusses the Maya glyph NA-ka-KAN, a glyph of a serpent deity conjured during bloodletting rites.
John Montgomery, Dictionary of Maya Hieroglyphics (New York: Hippocrene Books, Inc., 2002), 180
NA ka-KAN (Na Kan) T4.25.25:764a) n. deity name; serves as part of the name of one of the Vision Serpents conjured during bloodletting rites