Patronus

: "This ancient and mysterious charm conjures a magical guardian, a projection of all your most positive feelings. The Patronus Charm is difficult, and many witches and wizards are unable to produce a full, corporeal Patronus, a guardian which generally takes the shape of the animal with whom they share the deepest affinity. You may suspect, but you will never truly know what form your Patronus will take until you succeed in conjuring it."
: — Miranda Goshawk's overview of the Patronus Charm[src]
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The Patronus Charm (Expecto Patronum) was the most famous and one of the most powerful defensive charms known to wizardkind. It was an immensely complicated and extremely difficult spell, that channelled the caster's positive emotions into a powerful protection and evoked a partially-tangible positive energy force known as a Patronus (pl. Patronuses) or spirit guardian. It was the primary protection against Dementors and Lethifolds, against which there were no other defences.
There were two types of Patronuses: corporeal, which meant a Patronus with a particular shape and form, and incorporeal Patronuses. Incorporeal Patronuses had no particular shape and did not protect against Dementors the way corporeal Patronuses did, and has no hope of fending off scores of them like its more substantial counterpart would. However, some wizards like Remus Lupin chose to cast incorporeal Patronuses to hide their identity.
== Contents ==
* 1History
** 1.1Early history
** 1.2Second Wizarding War
** 1.3After the war
* 2Nature
* 3Casting
* 4Difficulty
** 4.1Worthiness
* 5The Patronus
** 5.1Incorporeal
** 5.2Corporeal
** 5.3Uses
* 6Patronuses and practitioners
* 7Patronus forms
* 8Etymology
* 9Behind the scenes
** 9.1Patronuses in the films
* 10Appearances
* 11Notes and references
== History ==
=== Early history ===
It is evident from old woodcuts and scrolls that the Patronus Charm had been used since ancient times. Therefore, it is unknown who created it, or when it was first invented. The charm also has a long association with those fighting for lofty or noble causes (those able to produce corporeal Patronuses were often elected to high office within the Wizengamot and Ministry of Magic).
According to legend, one of the most famous Patronuses of all time was a lowly mouse, which belonged to a young wizard called Illyius. Illyius cast the Patronus Charm when his village was being attacked by the Dark wizard Raczidian and his army of Dementors. Despite the mouse's diminutive size, it shone with a brilliant light, bringing the Dementors to a halt as it nimbly moved through the ranks of fleeing villagers. Enraged, Raczidian decided to enter the fray himself. He tried to summon a Patronus to ward off Illyius's mouse.
However, Raczidian failed to remember that only the pure of heart could produce a Patronus. Thus, for the first time in history, it was revealed what happened when a competent, but unworthy wizard or witch attempted the spell. Maggots shot out of Raczidian's wand and quickly devoured him as they engulfed his entire body. The villagers then hailed Illyius as a hero.
=== Second Wizarding War ===
: "And out of the end of his wand burst, not a shapeless cloud of mist, but a blinding, dazzling, silver animal. He screwed up his eyes, trying to see what it was. It looked like a horse. It was galloping silently away from him, across the black surface of the lake. He saw it lower its head and charge at the swarming dementors... "
: — Harry Potter's stag Patronus fending off hundreds of Dementors[src]
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Harry Potter took Anti-Dementor lessons with Remus Lupin in order to learn the advanced charm and so was one of the youngest to attempt this charm with actual results. During a Quidditch match against Ravenclaw in 1994, he cast his very first corporeal Patronus, when several Slytherin students were impersonating Dementors. He performed the charm again in June when he, along with Hermione Granger and Sirius Black, were being attacked by over a hundred Dementors, so he cast a corporeal Patronus powerful enough to drive them all away.
In 1995, Harry cast the charm against a Boggart that he thought was a Dementor during the third task of the Triwizard Tournament. The following summer, he and Dudley Dursley came under attack by two Dementors, and Harry managed to drive them away with the charm, leading to him being put on trial for underage magic in an attempt to discredit him.
Harry also taught the members of Dumbledore's Army the charm and some were even successful in casting it.
The charm was used frequently to ward off Dementors such as when The Trio escaped from the Ministry of Magic after obtaining the Horcrux locket and during the Battle of Hogwarts. Severus Snape also conjured his Doe Patronus to guide Harry to the hiding place of the Sword of Gryffindor.
The Order of the Phoenix would send out messages with their Patronuses such as Kingsley Shacklebolt and Arthur Weasley who in 1997 delivered warnings.
=== After the war ===
In 2011, Daniel Page, Ivy Warrington and their friend cast the Patronus Charm to fend off Dementors in the dungeon of Victor Gridley's caravan after practising it in the whole school year.
In 2020 of an alternate reality, Hermione Granger stopped Ron Weasley from casting the spell to drive off Dementors in order to buy time for Scorpius Malfoy to travel back in time and set things right. Severus Snape subsequently cast the spell, surprising Scorpius with its shape of a doe. Snape sent his Patronus to clear the way for Scorpius to reach the Great Lake, sacrificing himself in the process since the doe protected Scorpius instead of its caster. The doe disappeared when Snape was given the Dementor's Kiss, but succeeded in safely guiding Scorpius to the lake.
== Nature ==
: "Well, when it works correctly, it conjures up a Patronus, which is a kind of anti-Dementor — a guardian which acts as a shield between you and the Dementor. The Patronus is a kind of positive force, a projection of the very things that the Dementor feeds upon — hope, happiness, the desire to survive — but it cannot feel despair, as real humans can, so the Dementors can't hurt it. But I must warn you, Harry, that the Charm might be too advanced for you. Many qualified wizards have difficulty with it."
: — Remus Lupin explaining to Harry Potter the charm's nature[src]
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The Patronus represented that which was hidden, unknown but necessary within the personality. When a human was confronted with inhuman evil, such as the Dementor, they must draw upon resources he or she may never have needed, and the Patronus was the awakened secret self that lay dormant until needed, but which must now be brought to light.
Patronuses took forms that their casters might not expect, for which they had never felt a particular affinity, or (in rare cases) even recognised. Every Patronus was as unique as its creator and even identical twins had been known to produce very different Patronuses.
Given their long affinity with humans, it is perhaps unsurprising that among the most common Patronuses when cast (although it must be remembered that any corporeal Patronus was highly unusual) were dogs, cats, and horses.
The unusual witches and wizards who produced a Patronus that took the form of their favourite animal was an indicator of obsession or eccentricity. Here was a wizard who may not have been able to hide their essential self in common life, who may, indeed, have paraded tendencies that others might have preferred to conceal. Whatever the form of their Patronus, one would be well-advised to show respect, and occasionally caution, towards a witch or wizard who produced the Patronus of their choice.
Remus Lupin owned a spellbook which detailed the casting of the Patronus Charm.
== Casting ==
: Harry Potter: "And how do you conjure it?"
: Remus Lupin: "With an incantation, which will work only if you are concentrating, with all your might, on a single, very happy memory."
: — Discussion on how to conjure a Patronus[src]
To successfully cast the spell, one began by mustering the happiest memory they could think of (the happier the memory, the better the charm would work). Alternatively, one could imagine a scenario that would make for a very happy memory, as Harry did for his D.A.D.A. O.W.L. The next step was to begin drawing circles with their wand so as to increase the power of their spell. They must then say the incantation, Expecto Patronum; the Patronus would come from the tip of the wand and could be directed towards a target by pointing one's wand at said target.
The vast majority of witches and wizards were unable to produce any form of Patronus, and to create even an intangible one was generally considered a mark of superior magical ability. Rubeus Hagrid was an example of a wizard that couldn't conjure any form of Patronus, as the charm was too difficult for him. Alternatively, Minerva McGonagall was the only person seen to be able to produce three Patronus charms at once.
It was possible to disguise the form one's Patronus took, which was done both by Severus Snape to hide his love for Lily Evans, and by Remus Lupin, who felt it would give away his condition.
Also, some witches and wizards may have been unable to produce a Patronus at all until they had undergone some kind of psychic shock.
Although it was extremely hard to fully conjure a Patronus, in an alternate reality, fourth-years in Defence Against the Dark Arts class were tasked with casting this charm.
== Difficulty ==
: "That's very, very advanced magic."
: — The difficulty and complexity of the charm[src]
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The Patronus Charm was widely regarded as advanced magic, far beyond N.E.W.T.-level; in 1994 Remus Lupin stated that the charm was, in fact "ridiculously advanced". This charm was, indeed, so perilous, that few wizards/witches could conjure up a true Patronus. It was very complex and many qualified wizards and witches had trouble with it. In fact, Harry Potter was one of the youngest known wizards able to cast a Patronus; he was taught how to do so in early 1994 at the age of thirteen by Remus Lupin.
In a Dumbledore's Army lesson, Harry taught the members how to use the charm. Some were even successful in casting a corporeal form, though Harry said this might be because there was no Dementor to make them frightened. However, three members were later able to cast corporeal Patronuses in the presence of Dementors. Being able to cast a patronus, whilst fighting Dementors or not, was not required to graduate from Hogwarts, so it was something that was taught under special circumstances.
Amelia Bones and potential members of the D.A. were all very impressed when Harry Potter revealed that he could cast not only a Patronus Charm but a corporeal one to boot, which was notably more difficult than casting an incorporeal one, from as early as his third Hogwarts school year. Given that the success of the charm was directly reliant on the caster retaining a particular mental state, the Charm was more difficult to cast in emotionally trying circumstances. For instance, Harry Potter, Ron Weasley, and Hermione Granger all had difficulty casting their Patronuses when under the negative influence of Salazar Slytherin's Locket, one of Lord Voldemort's Horcruxes, and after witnessing the death of Fred Weasley in the final battle. This feature of the Charm was particularly unfortunate since the Charm's primary use was to defend against Dementors, dark creatures specifically equipped to mentally unhinge people (and hence was partly why it was regarded as such advanced, difficult magic).
Self-confidence might also play an important role in casting the spell. In 1994, Harry was able to cast the spell successfully, driving off a large number of Dementors in the process (which, according to Severus Snape, was only achievable by a very powerful wizard), thus saving Sirius and a younger version of himself, seemingly without recalling a happy memory, when he realised that he had already done it, although Harry could have had a 'happy memory' upon realising that he had saved all three of their souls.
=== Worthiness ===
: "While there is a widespread and justified belief that a wizard who is not pure of heart cannot produce a successful Patronus (the most famous example of the spell backfiring is that of the Dark wizard Raczidian, who was devoured by maggots), a rare few witches and wizards of questionable morals have succeeded in producing the Charm..."
: — It's rare for a Dark wizard to successfully conjure a Patronus[src]
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It was a general belief held by the wizarding world that only those who were pure of heart were able to cast Patronuses; this, however, was untrue, as several characters with negative personality traits were able to cast a fully-fledged Patronus. Although generally dark witches and wizards would not try to produce a Patronus, not having any need for one, most dark wizards would be devoured by maggots coming from their wand and consuming the caster.
For this reason, Lord Voldemort and his Death Eaters were not able to cast a Patronus Charm (not that it was necessary, as they already had the dark creatures under their control via their affinity to darkness, and would have no use for Patronuses). Draco Malfoy numbered among those unable to cast the Patronus Charm. Severus Snape was the only Death Eater capable of casting the charm.
Some witches and wizards of questionable morals, such as Dolores Umbridge, were able to produce corporeal Patronuses. Merula Snyde could only conjure an incorporeal Patronus, though it should be noted that she was only a fourth-year at the time and it was an advanced spell; the only other wizards known to produce a corporeal Patronus by that age were Harry Potter, Nymphadora Tonks, and Jacob's sibling.
Patricia Rakepick was a dark witch who sadistically tortured Merula Snyde with the Cruciatus Curse and murdered Rowan Khanna with the Killing Curse, and yet was able to cast a corporeal Patronus in the form of a lioness.
== The Patronus ==
A successfully conjured Patronus could take two forms: incorporeal and corporeal, and both types varied greatly in their appearances and strength.
=== Incorporeal ===
: "A thin wisp of silver escaped his wand and hovered like mist before him. "
: — Description of Harry Potter's incorporeal shield Patronus[src]
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An incorporeal Patronus was one which did not resemble any living creature and had few distinguishing features (if any). Incorporeal Patronuses resembled a burst of vapour or smoke without any clearly defined form shooting from the tip of the wand.
While they might be partially effective at halting Dementors (but not repelling them) and shielding the caster from them, incorporeal Patronuses were not "fully-fledged" Patronuses, and were regarded as a simpler and weaker version of the Charm. However, being able to cast even an incorporeal Patronus is still seen as an impressive feat.
=== Corporeal ===
: Harry Potter: "What does a Patronus look like?"
: Remus Lupin: "Each one is unique to the wizard who conjures it."
: — Discussion of corporeal forms a Patronus could take[src]
A corporeal Patronus was one that was fully-formed, taking the shape of a bright-silver, translucent animal. It was the strongest form a Patronus could take, being able to fully drive Dementors away. The specific animal forms that a corporeal Patronus took would vary from person to person and reflect each individual's innermost personality.
Patronus forms, however, were subject to change if the caster went through an emotional upheaval of some sort, including falling in eternal, unchanging love. For example, Nymphadora Tonks's Patronus changed from its previous form to that of a four-legged creature which others guessed was a wolf because then it would reflect her love for Remus Lupin, himself a werewolf. Another example was Severus Snape, whose Patronus was that of a doe, the same as Lily Evans, though this may have been the case all along rather than a change from its original form, as Snape was in love with Lily for most of his life.
Based on the fact that Patronuses were conjured by recalling happy memories, it stands to reason that a Patronus might change its form after one fell in love and the memories used to conjure the Patronus largely revolved around the person the caster was in love with. In addition, it seemed that some couples had "complementary" Patronuses (male and female forms of the same animal), such as Lily and James Potter. It is, however, unknown if this was a coincidence or not. If a wizard was an Animagus and could summon a corporeal Patronus, the two might take the same form. This was the case for Minerva McGonagall and James Potter.
Remus Lupin's Patronus took the form of a wolf, rather than a werewolf. Whether or not all werewolves would generate a similar Patronus is unknown. It stands to reason that it was likely due to Remus's best memories of his youth revolving around the acceptance he felt despite his condition, in which he felt more at home in his wolf form during those times, rather than cursed by it and also due to his nature as desiring a sense of belonging at his core, much like a true wolf.
Most Patronuses took the form of an ordinary animal. Magical creatures, such as Albus Dumbledore's phoenix Patronus, were uncommon. It was extremely rare for Patronuses to take the form of extinct animals. Hedley Fleetwood's woolly mammoth Patronus was a notable exception. Andros the Invincible was the only wizard capable of casting a Patronus the size of a giant, although whether it was a giant or not is unknown.
The corporeal Patronus was also better at repelling Dementors than the incorporeal form.
=== Uses ===
: "As a pure, protective magical concentration of happiness and hope (the recollection of a single talisman memory is essential in its creation) it is the only spell effective against Dementors."
: — The Patronus is the only known method of defence against a Dementor[src]
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There were two known uses for the Patronus Charm. The first and main use of the Patronus was to drive off certain dark creatures, such as Dementors and Lethifolds and was the only known charm that would work against them. As Dementors fed on happy memories, causing humans to drown in their own sorrow and sadness, the Patronus acted as a shield of sorts, of which the Dementor would try to feed off instead — the Patronus was comprised exclusively of positive feelings and couldn't comprehend negative emotion, so the Dementor's influence couldn't affect it.
The other use was devised by Albus Dumbledore, who invented a way of using the Patronus (corporeal and incorporeal) as a means of communication. They could deliver messages, speaking with the voice of the caster. This source of communication was believed to be exclusive to the members of the Order of the Phoenix. Using the Patronus for communication offered great advantages in security, as Patronuses identified the caster and were Dark Arts-proof. A good example of this was when Minerva McGonagall used her feline Patronus to call for help to the other Heads of Houses in 1998, when she found out that Harry Potter had returned to Hogwarts in search of Rowena Ravenclaw's Diadem.
Multiple Patronuses could be cast for communication, as McGonagall was able to create three. Another was when Severus Snape used his Patronus to lead Harry Potter to a pool in the Forest of Dean in 1997, where he had laid the Sword of Gryffindor for Harry to retrieve. It is unknown if Snape had conjured the Patronus with instructions or if he was hiding and controlling it for this task. Harry's Patronus was able to follow both oral and physical commands. They also only remained active whilst the caster was focusing on them. If they were not protecting anyone, Patronuses seemed to take on the traits of the creature they resembled and generally followed their caster around. This made it unsure whether or not they were sentient.
== Patronuses and practitioners ==
: "The majority of witches and wizards are unable to produce Patronuses and to do so is generally considered a mark of superior magical ability."
: — Only a select few witches and wizards can cast a Patronus[src]
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Witch/wizard 	Patronal form 	Notes
Andros the Invincible	Something allegedly the size of a giant 	Stated on his Chocolate Frog Card as the only wizard to make a Patronus that size.
Illyius 	Mouse 	Initially, Illyius's fellow villagers mocked him as they had never seen such a small and weak-looking Patronus, which corresponded to Illyius's timidity and for being tongue-tied. However, when the Dark Wizard Raczidian invaded and terrorised the village with his army of Dementors, Illyius's mouse Patronus proved to be stronger than the others, making him a hero.
Flavius Belby 	Something with horns 	In Fantastic Beasts and Where to Find Them, it is recorded that he cast off a Lethifold by performing the Patronus Charm. It says the Lethifold was thrown into the air on the horns of his Patronus.
Cho Chang 	Swan 	Seen in the last Dumbledore's Army meeting in 1996.
Aberforth Dumbledore 	Goat 	Summoned outside the Hog's Head in an attempt to convince the Death Eaters who had seen Harry's Patronus that they really saw a goat.
Albus Dumbledore 	Phoenix 	The bird whose loyalty he earned, Fawkes, was a phoenix. He used it in 1995 as a message to Hagrid when Krum was stunned. It was described as "a ghostly bird that flew off in the direction of Hagrid's house". A rare form.
Seamus Finnigan 	Fox 	He could not produce a fully formed corporeal Patronus in Dumbledore's Army, though, in the Battle of Hogwarts in 1998, he managed to conjure a Patronus in the shape of a fox.
Hedley Fleetwood 	Woolly mammoth 	An unusual form due to the extreme rarity of Patronuses based on extinct animals.
Hermione Granger 	Otter 	Seen in the last Dumbledore's Army meeting in 1996. It is apparently the only spell Hermione had trouble with, as said in 1997 while escaping from the Ministry of Magic.
Harry Potter 	Stag 	Harry's Patronus was in the shape of his father's Animagus form and Patronus. He learned how to conjure a Patronus at an exceptionally young age.
James Potter 	Stag 	James' Animagus form was also that of a stag.
Luna Lovegood 	Hare 	Seen in the last Dumbledore's Army meeting in 1996 and in the Battle of Hogwarts in 1998.
Ernie Macmillan 	Boar 	Seen in the Battle of Hogwarts in 1998.
Minerva McGonagall 	Cat 	Just before the Battle of Hogwarts, she sent her Patronus out to alert the other Heads of House that Hogwarts Castle would soon be under attack by Lord Voldemort and his followers.
Dolores Umbridge 	Cat 	While interrogating Muggle-borns at a trial, she had cast a Patronus to ward the Dementors from the prosecutors. Her favourite animal, as shown by the many plates with cats on them in her office. She was able to cast the Patronus due to her affinity with the locket Horcrux's evil influence.
Lily Potter 	Doe 	Mentioned in conjunction with Snape's Patronus. It was also the female form of her husband's Patronus.
Severus Snape 	Doe 	Acted as Harry's guide through the woods to where Godric Gryffindor's Sword was hidden. Snape's Patronus mirrored Lily's due to his unspoken love for her that began when they were small children.
Severus Snape 	Doe 	Cast by Severus Snape to aid Scorpius Malfoy and himself in the alternate reality created by Albus Potter and Scorpius in 2020.
Symposia Rawle 	Ladybird 	An unusual form that was very powerful despite its tiny size.
Kingsley Shacklebolt 	Lynx 	Seen in 1997 when he warned the Order during Bill and Fleur's wedding of the downfall of the Ministry of Magic and Rufus Scrimgeour's death.
Nymphadora Tonks 	Jack rabbit 	Tonks learned the Patronus Charm at some point by or during her fourth year. Her Patronus originally took the form of a jackrabbit.
Nymphadora Tonks 	Wolf 	The form of Tonks' Patronus changed in 1996. It became a wolf due to her love for Remus Lupin. Changes of Patronus are rare and usually caused by devastating life traumas. Occasionally when a witch and a wizard are married, their Patronuses will match each other (most likely because the witch/wizard's happy thought will be that of their spouse).
Remus Lupin 	Wolf 	Remus often deliberately disguised the form of his Patronus, usually by casting it as an incorporeal one, because he felt that it would give away too much about his lycanthropy.
Arthur Weasley 	Weasel 	First seen when he sent a message about Rufus Scrimgeour's arrival on Harry's seventeenth birthday. Later seen when Arthur sent a Patronus to 12 Grimmauld Place to inform Harry, Ron and Hermione that the Weasley family was safe.
Ginny Weasley 	Horse 	Seen in the last Dumbledore's Army meeting in 1996.
Ron Weasley 	Jack Russell terrier 	Seen in the last Dumbledore's Army meeting in 1996 and in the Battle of Hogwarts in 1998.
Jacob's sibling 	Either a white stallion, unicorn, Abraxan, tiger, cheetah, leopard, Spotted Hare, Mountain Hare or Lop-Eared Rabbit	In their fourth year, they learnt the charm under Tonks' tutelage.
Patricia Rakepick 	Lioness 	An unusual form, as lions were not native to Great Britain. Used it to banish several Dementors in the Forbidden Forest in 1990.
Miriam Strout 	White Swan 	Her Patronus changed to this form to commemorate Talbott Winger's mother, a White Swan Animagus and colleague Healer at St Mungo's.
Constance Pickering 	Unicorn 	A rare form, given how a unicorn is a magical creature.
Daniel Page 	Black cat 	Mastered the charm at a very young age.
Lottie Turner 	Hummingbird 	Mastered the charm at a very young age.
Cassandra Vole 	Mink 	Mastered the charm at a very young age.
Colby Frey 	Crocodile 	Mastered the charm at a very young age.
Fischer Frey 	Rhinoceros 	Mastered the charm at a very young age.
Ivy Warrington 	Pekingese 	Mastered the charm at a very young age.
== Patronus forms ==
Aardvark
Abraxan Winged Horse
Adder
Albatross
Badger
Basset Hound
Bat
Bay Mare
Bay Stallion
Beagle
Black cat
Black and white cat
Black Bear
Blackbird
Black Mamba
Black Mare
Black Stallion
Black Swan
Bloodhound
Borzoi
Brown Bear
Brown Hare
Brown owl
Buffalo
Buzzard
Calico cat
Capuchin Monkey
Cat
Cheetah
Chestnut Mare
Chestnut Stallion
Chow Dog
Crow
Dapple Grey Mare
Dapple Grey Stallion
Deerhound
Doe
Dolphin
Dragon
Dragonfly
Dun Mare
Dun Stallion
Eagle
Eagle owl
Elephant
Erumpent
Falcon
Field Mouse
Fire Dwelling Salamander
Fox
Fox Terrier
Ginger cat
Goat
Goshawk
Granian Winged Horse
Grass Snake
Great Grey Owl
Greyhound
Grey Squirrel
Hedgehog
Heron
Hippogriff
Hummingbird
Husky
Hyena
Ibizan Hound
Impala
Irish Wolfhound
Jack Rabbit
Jack Russell terrier
King Cobra
Kingfisher
Leopard
Leopardess
Lion
Lioness
Little Owl
Lynx
Magpie
Manx Cat
Marsh Harrier
Mastiff
Mink
Mole
Mongrel Dog
Mountain Hare
Nebelung Cat
Newfoundland
Nightjar
Occamy
Ocicat
Orangutan
Orca
Oryx
Osprey
Otter
Peacock
Persian cat
Phoenix
Pheasant
Piebald Mare
Piebald Stallion
Pine Marten
Polar Bear
Polecat
Python
Ragdoll cat
Rat
Rattlesnake
Raven
Red Squirrel
Rhinoceros
Robin
Rottweiler
Runespoor
Russian Blue Cat
Salmon
Scops owl
Seal
Shark
Shrew
Siberian Cat
Snowy owl
Sparrow
Sparrowhawk
Spotted Hare
Sphynx cat
Stag
St Bernard
Stoat
Swallow
Swan
Swift
Thestral
Tiger
Tigress
Tonkinese cat
Tortoiseshell cat
Unicorn
Vole
Vulture
Weasel
West Highland Terrier
White Mare
White Stallion
White Swan
Wild Boar
Wildcat
Wild Rabbit
Wolf
Wood Mouse
* Crocodile
* Pekingese
== Etymology ==
Patronus is the nominative singular case meaning "protector", "guardian", or simply "patron" in Latin, specifically reflecting the entire role that the Patronus Charm plays. In archaic Latin, it meant "father", which is very interesting, considering that Harry Potter's Patronus is the same as his father's Patronus and Animagus form, a stag. The Latin word exspecto is the first person singular form of exspectare meaning "to await", thus the charm's incantation translates into "I await a patron" (since patronum is the singular accusative form of patronus, meaning it is the case which a noun or an adjective describing the noun takes when it is the direct object of a sentence, which in the spell's translation, it is).
== Behind the scenes ==
: " [...] the Patronus often mutates to take the image of the love of one's life (because they so often become the 'happy thought' that generates a Patronus). "
: — J. K. Rowling[src]
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* Two Patronuses planned for the films but ultimately cut included a Thestral and a chimpanzee.
* The Patronuses of James Potter and Minerva McGonagall match their respective Animagi form. These are the only characters whose Patronus and Animagus forms are known. However, not all Animagi have the same animal as their Patronus and Animagus.
** Similarly Remus Lupin's Patronus is a wolf, but whether this is universal among werewolves or not is unknown.
* In Harry Potter and the Prisoner of Azkaban, when Dementors attack Harry, Hermione and Sirius, Harry's Patronus is very weak and thin (based on how there were tons of Dementors) yet the Dementors were still unable to pass through it. One Dementor was able to make it vanish by gesturing at it though.
* In the first chapter of Harry Potter and the Deathly Hallows, a white peacock appears in the gardens of Malfoy Manor. Some fans believed this bird to be Lucius Malfoy's Patronus. However, J. K. Rowling stated that no Death Eater except Severus Snape could (or had a need to) conjure a Patronus, because Death Eaters fight alongside that which Patronuses fight against. This means that the peacock was in fact a living creature. It is stated in Harry Potter and the Deathly Hallows that the creature was in fact an albino peacock.
* In the video game adaptation of Harry Potter and the Prisoner of Azkaban, the more moderate Expecto Patronum is a ball of light.
** In the console versions, it works as a guided-missile that can only be steered left or right, and accelerate.
** In the PC version, before being cast, a white ring goes up Harry's arm and if it reaches the top of the wand, Harry has to try the spell again, and it is used only to attack Dementors (it also produces lightning effects). At the climax of the game, a stag (Harry's Patronus) jumps out of the wand to drive away all the Dementors nearby attacking Harry and Sirius, and its during that battle in the console versions, Harry's Patronus changes into a stag with altered controls.
* In the said video game, the first video game adaption of Harry Potter and the Deathly Hallows, and LEGO Harry Potter: Years 1-4/LEGO Harry Potter: Years 5-7 the Patronus Charm appears to push the Dementors away with the first shot, and a second shot kills them.
* The lecture that Harry gives on Patronuses to Dumbledore's Army in the film adaptation of Harry Potter and the Order of the Phoenix is extremely similar to the lecture Remus Lupin gave him in the film adaptation of Harry Potter and the Prisoner of Azkaban.
* In Harry Potter and the Deathly Hallows: Part 1, Dolores Umbridge's Patronus seems to emanate a shield that keeps the Dementors separated from everyone in the courtroom. In addition, Kingsley Shacklebolt's Patronus is described in the novel as taking the form of a lynx; however, in the film it is depicted as a shimmering comet of light from which springs silvery images of witches and wizards screaming in terror as Kingsley's voice details the death of Scrimgeour and the fall of the Ministry.
* In LEGO Harry Potter: Years 1-4, Voldemort, Lucius Malfoy, Walden Macnair, Barty Crouch Jnr, and an unnamed Death Eater can all cast the spell, despite the fact that Rowling stated that no Death Eater besides Severus Snape could produce a Patronus. It is most likely that this was simply incorporated for gameplay purposes.
* According to W.O.M.B.A.T., it is possible that Patronuses vary in strength according to which animal's form they take. Later canon from Wonderbook: Book of Spells, however, stresses that this is not the case and that the form of the animal has no correlation to the strength of the Patronus (see, for instance, Illyius and Symposia Rawle).
* J. K. Rowling stated that the happy memory that would produce the strongest Patronus for her would be the births of any of her three children, though a close fourth would be when she learned that Harry Potter and the Philosopher's Stone was going to be published. She has also stated that she'd like for her Patronus to be an otter, like Hermione's, but she has a feeling it might actually be a large dog. However, in a message on Twitter in 2014, she claimed it would be a pine marten. Additionally, in a 2000 interview, she stated that the Patronus Charm was her favourite spell in the series so far. Rowling later revealed that a pine marten was what she had tested as in the initial form of the Patronus test that was later posted on Pottermore. She took the test again in its final form and tested as a heron.
* Learning to cast a Patronus is one of the tasks given to the player in the final Chapter of the game Wonderbook: Book of Spells. For learning the incantation and gesture, the player is given the Trophy "Expecto Patronum!" On the next page, the player is given the chance to cast a true Patronus, the form of which is apparently chosen randomly. Amongst the possible Patronuses are a bat, a bull, a cat, a goat, a horse, a rabbit, a scorpion and a snake. For discovering their Patronus, the player is awarded the Trophy "True Patronus."
* J. K. Rowling has stated the only way that a Patronus is able to change its current form is through eternal unchangable love.
* Although J. K. Rowling has stated that the plural form is Patronuses and not Patroni, the German translation always translates it as Patroni.
* On 22 September, 2016, Pottermore unveiled the long-awaited and discussed option for members of the site to determine their patronus. This takes the form of a quiz of several questions that can only be taken once, at which point the member's Patronus is revealed and added to their member profile.
* When J. K. Rowling was asked about the form of Newton Scamander's Patronus, she said that it would be a spoiler to future films of the Fantastic Beasts series.
* On Pottermore (and in other releases), a few animals such as horses, cats, squirrells and swans, have Patronuses in different hair colours of the animal. It is unknown how hard the difference is to tell in-universe, since all Patronuses are silver in colour, and therefore all look the same (aside from their forms).
=== Patronuses in the films ===
* In the film adaptation of Harry Potter and the Order of the Phoenix, Harry's Patronus physically attacks the Dementors by charging at them, as depicted in the books, with the first successful patronus shield he conjured being used to force a Boggart in the form of a Dementor back into its trunk. Also, Patronuses produced by the members of Dumbledore's Army make noises and are capable of interacting with physical objects, such as Ron's dog Patronus knocking over Neville Longbottom. Also, in Harry Potter and the Deathly Hallows: Part 1, Umbridge's Patronus was heard hissing.
* There was a noted change in appearance of Patronuses in general in the Order of the Phoenix film. In films 5-8, Patronuses appear to be very wispy and airy, while in the third film they look more substantial, solid and brighter.
* In Harry Potter and the Deathly Hallows: Part 1, during the infiltration of the Ministry of Magic, Umbridge's Patronus was very clearly seen several times in the same scene and often looked less like a cat and more like a reanimated, feline corpse, with the skeletal features visible. This is odd for a Patronus (they usually look quite 'alive' and well) and its twisted form may be a nod to both Umbridge's nature and the circumstances under which it was cast.
* In the film adaptation of Harry Potter and the Prisoner of Azkaban, the Patronus in its powerful wave-like form emits a deep reverberating sound. In Harry Potter and the Deathly Hallows: Part 2, this effect was also used when Aberforth Dumbledore protected Hogwarts from Dementors.