Snakes are often associated with immortality, rejuvenation, rebirth and youth.
One reason is that in the days before humans had time to study the life-cycles of animals it was believed that when a snake shed its skin it actually got younger and could potentially live forever. When a snake sheds its skin it appears to be ill and when it finishes shedding its skin, it looks rejuvenated and reincarnated. This is part of why a snake is on the rod of asclepius, which represents medicine (as well as the caduceus, which it is often confused with). Snake venom may also be used to restore, heal, or grant immortality, in fiction and even real life.
Another reason why snakes are thought to represent immortality is because of the Ouroboros, a snake symbol that forms a circle by eating its own tail. Circles and spirals were used as symbols for eternal life. Sometimes, the snake will have two knots to resemble the infinity symbol.
- Naruto's original prime villain, Orochimaru, had a decidedly serpentine motif (he's named after a mythical character who is in turn named after a hydra-like monster), with matching snakelike face, and the ability to summon giant snakes. His "true form" is even a massive serpent made up of smaller snakes. He got these attributes in his search for a technique to bestow immortality. The degree of similarity with Voldemort is staggering, and both are examples of this trope meeting Reptiles Are Abhorrent.
- Also, Kabuto who absorbs Orochimaru's powers, looks even more serpentine and does a technique that resurrects and controls dead shinobi to fight for him as undead zombies. So there you go.
- He likens himself as surpassing the serpent into a dragon.
- Anacondas: The Hunt for the Blood Orchid: The main characters are seeking a flower, the Blood Orchid, which contains chemicals that can prolong life when eaten. However, the anacondas in the area have been feeding on animals which fed on the flower, and as reptiles don't stop growing, the jungle is now packed with very large, very old snakes that have gathered for the mating season.
- Harry Potter:
- The closer to immortality Voldemort got, the more snake-like he seemed. Also, Voldemort took a piece of his soul and made his pet snake Nagini a Horcrux probably making her a immortal.
- In Harry Potter and the Chamber of Secrets, the basilisk that lives beneath the school has an incredibly long lifespan. It was first stored under the school around a thousand years earlier.
- In The Neverending Story (both the book and movies,) this is the visual motif behind AURYN, the amulet representing the power of the immortal Childlike Empress.
- In The Wheel of Time, the Dragon is a person who is reincarnated once an Age to deal with the Dark One. The motif of immortality is clearly in use, especially as the Dragon emblem looks decidedly snakelike, and the series makes varied use of the Ouroboros symbol for the Wheel of Time itself.
- Invoked in-universe in The Sleeping Beauty. When Godmother Lily is undoing the "look like she's dead" spell on Rosa, one component of the ritual is a snake ring on Rosa's hand to symbolize rebirth.
- In My Ragnarok (a Spin-Off of the Labyrinths of Echo series), Jormungandr the World Serpent arrives to grant immortality to Max and his army. Too bad Max kills its instead.
- The Shalis in The Licanius Trilogy are serpent-like beings that can always be revived after death if they aren't revived in about a day's time, though, they will go completely insane.
- Queen Salmissra from The Belgariad also invokes this trope. The patron god of Nyissa is a snake god who favored a mortal priestess a long time ago, but neglected to prolong her life. After her death, each reigning queen is chosen based on how closely they resemble Salmissra and kept artificially young through drugs, and replaced when they grow too old for this to work. In effect, this means that it appears to uninformed outsiders Nyissa, favored by the serpent god Issa, has its monarch blessed with immortality and eternal youth. Unfortunately, the realization that she is not immortal drives one Salmissranote into rather immoral actions under the promise of immortality, until Polgara transforms her into an immortal snake.
- The Worm of the World's End in The Chronicles of Thomas Covenant probably counts. It's apparently a gigantic serpent that forms the foundation of the world itself, and if it ever wakes up it'll be the end (probable reference to Jormungandr). Lucky there's no chance of that ever hap... oh, shit...
- Doctor Who: The Master's ashes inexplicably turn into a CGI snake during the Eighth Doctor TV movie. It sabotages the TARDIS, escapes onto Earth and possesses a human.
- The Bible:
- In the book of Numbers, the children of Israel were dying from being bitten by fiery serpents. Moses made a brass serpent and put it on a pole, and whoever looked at it didn't die from snakebite.
- John 3:13: "And as Moses lifted up the serpent in the wilderness, even so must the Son of man be lifted up." So the serpent symbolizes Christ, crucified and resurrected.
- In The Epic of Gilgamesh, the herb of eternal life that Gilgamesh sought to cheat death with was stolen and eaten by a snake, giving it the ability to shed its skin, thus rejuvenating itself and becoming immortal.
- Asclepius, the Greek God of Healing, is symbolized by one serpent coiled round a staff: this image is still today used as a sign of regeneration, healing and medicine and is at least two thousand years old. The Asclepius staff is the cap badge of the British Army's medical corps. The symbol may be older still: refer to the example from Numbers, concerning Moses' staff with the serpent coiled round it, that conferred immunity from snakebite and by extention deliverance from evil and death - Satan in his Garden of Eden serpent form.
- In Hindu Mythology, much like with Gilgamesh, Garuda, king of the birds, was sent to retrieve an elixir of immortality, but lost it in an accident. Snakes took the opportunity to lap up the spilled drops, gaining their skin-shedding rejuvenation, but cut their tongues on the grass, gaining their forked tongues.
- Níðhöggr, the dragon/snake monster chewing on the roots of Yggdrasil in Norse Mythology, is one of the few beings that will survive Ragnarök.
- In Shadowrun shamen who have Snake as their totem gain +2 dice when casting healing spells.
- Pokémon has the "Shed Skin" ability that has a chance of healing Standard Status Effects each turn, possessed by the snake-like Pokemon Ekans, Dratini and Seviper (among others).
- Monks that specialize in healing their allies in World of Warcraft have a heavy serpent motif — they fight in a specialized Serpent Stance, lay down Serpent Statues that duplicate healing, etc.
- In BlazBlue Hazama (or more specifically Yuuki Terumi), who is always associated with snakes, turns out to be very old. As in, nearly as old as the BlazBlue universe itself as the original will of the Susanooh Unit that protects the Master Unit Amaterasu.
- Dark Souls: Serpents are closely tied to the idea of immortality, and Dark Souls lore states that serpents are "incomplete dragons", the Everlasting Dragons having been the only truly immortal beings in the verse. They are also symbols of greed, so the general symbolism of a snake in Dark Souls is something that covets immortality, but cannot quite attain it. The Primordial Serpents are also extremely old, supposedly having existed prior to the Age of Fire, if their name is any indication. The Japanese dialogue in the third game suggests, however, that at least one of the Primordial Serpents, Kaathe, is dead by that time, meaning they are not truly immortal either.