It's one of the most famous instances of Animal Jingoism out there. Mongoosesnote — weasel-like carnivores belonging to the family Herpestidae — are universally thought of as the mortal enemies of snakes. The snake can be one of many kinds, but it's usually a cobra, especially if the work is set in the Middle East or India. Cobras play a major role in the lore of both of these places, and mongooses were renowned for their ability to hunt and kill them while evading their venomous fangs.
The association of mongooses with cobras specifically was introduced to the world at large in Rikki-Tikki-Tavi, a story from The Jungle Book. Many depictions of the animosity between mongooses and snakes since then have been based on the one in that story, with the mongoose as a heroic defender of the innocent and the snake as a cruel, cunning villain. This dichotomy extends even to fantasy creatures, as the Basilisk and Cockatrice's reputed arch-enemy is the weasel, which may be based on travelers' tales of mongooses killing cobras (people in medieval Europe did not know what a mongoose was, but were familiar with weasels). It is worth noting that in Real Life, mongooses do not actively seek out snakes in preference to other prey—they feed mainly on other small mammals. However, their legendary ability to kill snakes has made them popular as semi-domesticated pets in India and the Middle East.
If a mongoose and a snake are on opposing sides, the mongoose will typically default to the heroic position, since Snakes Are Sinister, however this is not necessary and it is entirely possible for the trope to be neutral in its portrayal. If this is the case, and neither the mongoose nor the snake are depicted as good or evil, then the emphasis is usually on their opposing natures rather than the desire of the mongoose to kill the snake.
Even if a work doesn't actually depict the two animals fighting, the image of the mongoose and the cobra as mortal enemies is such a popular one that it has become a common visual shorthand in visual media for two evenly-matched adversaries.
- The page image is from the episode "The Ghost of Maiden's Peak", in which a Gastly transforms into a mongoose (as in, an actual real-world, non-superpowered mongoose, and not a mongoose-like Pokémon, as Zangoose had yet to be created at the time) to scare Jessie's Ekans. The games would later take the trope to its obvious conclusion, as noted below and in the Video Games section.
- Jessie herself later acquires a Seviper, a snake Pokémon noted for its rivalry with the mongoose-based Zangoose, resulting in a minor Running Gag where Seviper would drop everything and disobey Jessie if there was a Zangoose around.
- YuruYuri: The anime adaptation uses a mongoose and a snake to represent the rivalry between Sakurako and Himawari.
- Love Pistols: Subverted — Shima, the mongoose, is in love with Aogiri, the viper.
- In Kodocha, "natural enemies" Sana and Akito are represented as a mongoose and cobra, respectively.
- Revolutionary Girl Utena: In one episode, Nanami is trying to ruin Anthy's reputation, and one of her plans is to hide a snake in Anthy's home and spread rumours that Anthy is the kind of girl who keeps snakes - her plan fails when Anthy's pet mongoose eats the snake.
- Magical Witch Punie-chan: In Episode 3, Elise summons some cobras to attack Punie, who summons some mongoose to counter this. The result is a rather gory scene of the mongoose killing and eating the cobras.
- In The Morose Mononokean, Abeno alludes to the snake vs. mongoose when Ashiya suggests pitting himself against the human-hating Executive to help him activate and control his "influence" powers. Abeno warns that the intended practice would just devolve into a death-match if this triggers Sakae's demon-hating personality that's residing inside Ashiya.
- Marvel Universe: The Whizzer is a rather bizarre take on this trope. He was bitten by a snake and saved with an infusion of mongoose blood, which gave him Super Speed... somehow.
- The DCU: The first transformation Beast Boy was able to perform was transforming into a lime green mongoose to protect his parents from a cobra.
- G.I. Joe: A Real American Hero (Marvel): Destro has a sculpture of a mongoose and a cobra on his desk.
- Chuck Jones's adaptation of Rikki-Tikki-Tavi: It's an adaptation of the Trope Codifier, Rudyard Kipling's story about a heroic mongoose saving the humans who adopted him from a family of cobras.
- The Brave Little Toaster to the Rescue, Murgatroid the snake describes how Rob once saved him from a mongoose. In the United States.
- Casino Royale (2006) opens to a group of gamblers betting on a fight between a mongoose and a cobra.
- In Austin Powers: The Spy Who Shagged Me, Dr. Evil says, "Austin Powers... he's the snake to my mongoose, or the mongoose to my snake. Either way it's bad. I don't know animals."
- While it doesn't depict an actual snake or mongoose, Snake and Mongoose is about one of the greatest rivalries in drag racing history, so it was definitely named in reference to this trope.
- Fangs of the Cobra has a fight scene between a cobra and a mongoose staged onscreen, with gory results. Being a Hong Kong film PETA really doesn't have a say about actual animal cruelty being depicted for entertainment.
- Rikki-Tikki-Tavi from The Jungle Book is probably the Trope Codifier for modern audiences, establishing the mongoose and the snake as enemies in pop-consciousness.
- In Timothy Zahn's The Cobra Trilogy, the titular Cobras are actually Super Soldiers, and the project devised to counter them is called "Mangus", which sounds like "Mongoose".
- The Panchatantra plays this trope straight with a tragic ending, as the mongoose saves a baby from a venomous snake, only to be killed by the baby's mother, who assumes the blood on its maw is the baby's.
- Alluded to on a larger scale in The Priory of the Orange Tree, where the dragon-fighting priory of the title employs ichneumons, depicted here as mongooses big enough to ride and natural serpent-killers.
- In the first book of the French-Canadian fantasy series Amos Daragon, the titular teenage protagonist orders his army of knights to carry mongooses in cages, since they'll be going up against basilisks. The titular basilisks are slaughtered.
- Wayne and Shuster had a sketch where Johnny Wayne plays a detective who discovers that Frank Shuster's character is the villain. The villain tries to get away by wielding a snake as a weapon to ward off pursuers, but when he gets out of sight, Wayne's character is relaxed considering the villain is heading for the mongoose compound. Sure enough, the mongoose makes short work of the snake.
- Alluded to in Once Upon a Time. In Season 1, Henry recruits Emma (his birth mother) to defeat Regina (his adoptive mother) and restore everyone else's happy ending. He dubs the plan "Operation Cobra". A few seasons later, he's working with a post HeelFace Turn Regina so that she can get her happy ending. Upon learning the name of the old plan, she immediately decides this one will be "Operation Mongoose".
- "Cobra vs. Mongoose" by Shonen Knife alludes to the rivalry between the cobra and the Mongoose.
- A drag racing friendly rivalry in The '70s involved Don "The Snake" Prudhomme and Tom "The Mongoose" McEwen; their "funny cars" were decorated in their respective motifs. Both were fierce competitors, accomplished drivers, and had top-tier mechanics and underlings in their retinues, which made these men the face of funny car drag racing during that decade.
- There was a Beanie Babies character named Runner the Mongoose, whose poem was all about how much he loved to kill snakes. He was quickly retconned to an unspecified member of Mustelidae (weasel family), even though mongoose are not a member of that family.
- Mattel Toys made a series of Snake versus Mongoose die-cast model cars based around motorsports racers "Snake" Prudhomme and "Mongoose" McEwen. Mattel even became the pair's principal sponsor, keeping their funny cars and racing rivalry primed and topical for years, which in turn bolstered Mattel's Hot Wheels cars.
- The Pokémon Zangoose and Seviper are based on a mongoose and a snake respectively, and their defining traits are their mutual hatred of each other. In Pokémon X and Y, if you encounter them in a Horde Battle together, they will focus their attention on fighting each other instead of attacking your Pokémon!
- King's Quest V: Absence Makes the Heart Go Yonder!: ends with a wizard's duel a la Sword in the Stone between King Graham and the evil wizard Mordack. When Mordack becomes a cobra Graham turns into a mongoose. The manual actually calls this spell Rikki Tiki Tavi after the Rudyard Kipling story. It also speculates that people who knew of the story told the creator of the moongoose spell, who named it after it. Take this with a grain of salt, as Word of God puts the series in Earth's past, not a parallel dimension in intermittent contact with our present.
- Scriblenauts Unmasked, during the boss fight with Sinestro on Oa, Maxwell has to counter everything Sinestro creates with something that scares Sinestro's creation. One of the things Sinestro can summon is a snake, and the correct response from Maxwell is to create a mongoose.
- In My Gym Partner's a Monkey, there was an episode that lampshaded this trope. Slips the python befriends a mongoose but wonders how they can keep their friendship intact after learning from a documentary that they are supposed to be enemies.
- In He-Man and the Masters of the Universe (2002), Rattlor—a Snake Person—has a crippling fear of mongooses that Orko is more than happy to use against him.
- One episode of Wild Kratts features snakes and mongooses and shows a mongoose killing a snake, while explaining the physiological mechanism that allows the mongoose to be immune to the snake's venom.
- In Littlest Pet Shop (2012), Sunil the mongoose is terrified of everything, except cobras, which he will gladly beat the the ever-loving tar out of.
- The Simpsons: At the end of "Eight Misbehavin'", Homer and Butch Patrick do a show where they ride on a unicycle around a pit of cobras (and robots shaped like cobras). When the cobras start attacking Homer during his performance at the zoo, a mongoose is released to combat them, but decides to attack Homer instead.