The Phoenix symbolized rebirth in ancient Greece because it possessed regenerative powers and was also regarded as a symbol of immortality. The new HyFlex CM NiTi root canal files also have similar powers. They have properties not found in other root canal files because they are able to behave intelligently. The file responds intelligently to excessive resistance in the root canal by straightening its spirals, avoiding binding to the walls. This results in an excellent resistance to cyclic fatigue.