Ouroboros

[7][8] The ouroboros is often interpreted as a symbol for eternal cyclic renewal or a cycle of life, death and rebirth; the snake's skin-sloughing symbolises the transmigration of souls.

[9] One of the earliest known ouroboros motifs is found in the Enigmatic Book of the Netherworld, an ancient Egyptian funerary text in KV62, the tomb of Tutankhamun, in the 14th century BCE.

[12] The 4th-century CE Latin commentator Servius was aware of the Egyptian use of the symbol, noting that the image of a snake biting its tail represents the cyclical nature of the year.

[15] The famous ouroboros drawing from the early alchemical text, The Chrysopoeia of Cleopatra (Κλεοπάτρας χρυσοποιία), probably originally dating to the 3rd century Alexandria, but first known in a 10th-century copy, encloses the words hen to pan (ἓν τὸ πᾶν), "the all is one".

[17] In Norse mythology, the ouroboros appears as the serpent Jörmungandr, one of the three children of Loki and Angrboda, which grew so large that it could encircle the world and grasp its tail in its teeth.

In the legends of Ragnar Lodbrok, such as Ragnarssona þáttr, the Geatish king Herraud gives a small lindworm as a gift to his daughter Þóra Town-Hart after which it grows into a large serpent which encircles the girl's bower and bites itself in the tail.

[19] It is a common belief among indigenous people of the tropical lowlands of South America that waters at the edge of the world-disc are encircled by a snake, often an anaconda, biting its own tail.

According to the Zohar, the Leviathan is a singular creature with no mate, "its tail is placed in its mouth", while Rashi on Baba Batra 74b describes it as "twisting around and encompassing the entire world".

[22] According to the medieval Yoga-kundalini Upanishad: "The divine power, Kundalini, shines like the stem of a young lotus; like a snake, coiled round upon herself she holds her tail in her mouth and lies resting half asleep as the base of the body" (1.82).

The alchemists, who in their own way knew more about the nature of the individuation process than we moderns do, expressed this paradox through the symbol of the Ouroboros, the snake that eats its own tail.

He symbolizes the One, who proceeds from the clash of opposites, and he, therefore, constitutes the secret of the prima materia which ... unquestionably stems from man's unconscious.The Jungian psychologist Erich Neumann writes of it as a representation of the pre-ego "dawn state", depicting the undifferentiated infancy experience of both mankind and the individual child.

[25] The German organic chemist August Kekulé described the eureka moment when he realised the structure of benzene, after he saw a vision of Ouroboros:[26] I was sitting, writing at my text-book; but the work did not progress; my thoughts were elsewhere.

My mental eye, rendered more acute by the repeated visions of the kind, could now distinguish larger structures of manifold conformation: long rows, sometimes more closely fitted together; all twining and twisting in snake-like motion.

[27] Rees stressed "the intimate links between the microworld and the cosmos, symbolised by the ouraborus", as tail and head meet to complete the circle.

[29] Hence the snake eating its tail is an accepted image or metaphor in the autopoietic calculus for self-reference,[30] or self-indication, the logical processual notation for analysing and explaining self-producing autonomous systems and "the riddle of the living", developed by Francisco Varela.

[36] The genus of the armadillo girdled lizard, Ouroborus cataphractus, takes its name from the animal's defensive posture: curling into a ball and holding its own tail in its mouth.

[40] In The Wheel of Time and its 2021 television adaption, the Aes Sedai wear a "Great Serpent" ring, described as a snake consuming its own tail.

In Season 1 (2018) of the cyberpunk Netflix series Altered Carbon, the protagonist Takeshi Kovacs gets an ouroboros tattoo in shape of an infinity symbol, and it features in the show’s title sequence, tying in to the themes of rebirth and the twisting of the natural cycle of life and death.

[47] In the season 2 premiere of the television series Loki, a character named Ouroboros (played by Ke Huy Quan) is introduced.

In Xenoblade Chronicles 3, the player's party wields a power named after Ouroboros, which is subversively used to oppose the world's cycle of death and rebirth, rather than representing it.

A three-headed ouroboros is the logo of Elder Scrolls Online, with a lion, a dragon, and an eagle that represent the three main factions of the game.