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 moves inward: Carl Jung’s pre-ego dawn state and the integration of the shadow, August Kekule’s dream of a tail-biting snake that revealed the benzene ring, and the cybernetic concept of autopoiesis where a system consumes its own output to produce its own input.

• Why the tail-biting serpent became the global shorthand for eternity rather than a butterfly or shedding animal
• The Egyptian view of the loop as the boundary where chaos meets order and time begins and ends
• Alchemy’s cosmic recycling program and its intuition of conservation of matter
• Martin Rees’s cosmic Ouroboros linking the quantum tail to the galactic head
• Everyday echoes from the Spanish pescadilla to Heinlein’s All You Zombies and The Neverending Story’s AURYN