Kundalini is the Sanskrit name for the fire of the pentecost that empowers and awakens the apostles; it is the serpent raised by Moses. Kundalini is the energetic basis of becoming an angel, buddha, master, etc.
"Kundalini is the cosmic power in individual bodies. It is not a material force like electricity, magnetism, centripetal or centrifugal force. It is a spiritual potential Sakti or cosmic power. In reality it has no form." - Swami Sivananda