Ningizzida has been popularized in the 20th century by Raku Kei (Reiki, a.k.a. "The Way of the Fire Dragon"), where "Nin Giz Zida" is believed to be a fire serpent of Tibetan rather than Sumerian origin. "Nin Giz Zida" is another name for the ancient Hindu concept Kundalini, a Sanskrit word meaning either "coiled up" or "coiling like a snake". "Kundalini" refers to the mothering intelligence behind yogic awakening and spiritual maturation leading to altered states of consciousness. There are a number of other translations of the term, usually emphasizing a more serpentine nature to the word—e.g. "serpent power". It has been suggested by Joseph Campbell that the symbol of snakes coiled around a staff is an ancient representation of Kundalini physiology. The staff represents the spinal column, with the snake(s) being energy channels. In the case of two coiled snakes, they usually cross each other seven times, a possible reference to the seven energy centers called chakras.