When threatened, the armadillo girdled lizard of South Africa curls into a circle and bites its own tail, earning it the scientific name Ouroborus cataphractus and instinctively recreating one of humanity's oldest symbols. This episode traces the Ouroboros from its first known appearance on a golden shrine in Tutankhamun's tomb, where two serpents of the protector god Mehen encircle a fused figure of Ra and Osiris, through Roman-era talismans, Gnosticism, and the black-and-white drawing by Cleopatra the Alchemist inscribed with the words hen to pan, the all is one.

We then follow the symbol across cultures that never met: Jormungandr encircling the Norse world, Sigurd Snake-in-the-Eye's birthmark, the world-circling anaconda of South America, Kundalini and samsara in Indian thought, and the Leviathan of the Zohar. From there the serpent mov ...