Expecto Patronum is an incredibly beneficial spell in the Harry Potter universe, but the act of producing it requires a paradoxical combination of intense focus and letting go of one's anxiety (which is why it is claimed to be very rare.) As the only defensive measure to combat Dementors as well as Lethifolds, another dark beast that literally swallows its poor prey whole.

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The Patronus itself is also known as a "spirit guardian", and is described as a force emanating from positive emotions, regardless of what they might be. As much as fans know about this brand of magic, there remain a ton of unquantifiable factors that go into its historical usage.

How Was The Patronus Charm Created?

Harry Potter

Several ancient documents provide evidence that this spell has been employed for a millennium at least, which shrouds its historical origins. Why, because magic-users didn't have any methods for keeping information safe, like the muggles of their time?

This problem aside, the earliest knowledge about the Patronus Charm is that it has always been linked with the virtuous, especially those who fought against dark spirits and other evils in order to protect their loved ones. How does one come up with such a complex magic though?

What Does Their Form Depend On?

Long after the death of Lily Potter, her spirit (sort of) lived on within the heart of Severus Snape, explaining why he produces a doe. This obviously implies that the core emotions of a person have something to do with the anatomy of their Patronus, but not, for example, why Ron's is a Jack Russell Terrier, Hermione's an otter, and Ginny's a horse?

None of these creatures have been mentioned in the story, let alone associated in any way with these characters. Also, the specificity of Ron's Patronus makes it all the more confusing.

Why Are All Of Them Animals?

It would be weird to have a human being as one's Patronus, but there are a lot more living organisms than just animals, aren't there? Is it not possible for at least a few of the tens of thousands of wizards and witches living in the current era to identify more with, say, a plant?

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Rita Skeeter's is said to be a beetle, the same form as her animagus, so insects are clearly included. Why not fungi, or bacteria, or Deep-sea Angler Fish? Some of these would have definitely made the story a lot more interesting.

Why Are Magical Patronuses So Rare?

Dumbledore's phoenix Patronus

Continuing on from the previous point, let's assume that it can only be animals. Then why aren't there a lot of magical animals in the list of known Patronuses? Dumbledore's is a Phoenix, one of the most mysterious creatures in Harry Potter, so there technically should be others, like Thestrals, Hippogriffs, and so on.

But their almost total lack of presence is a bit disconcerting, mainly because the characters are literally steeped in magic to the point that some of them don't even know what electricity is. Also, can aggressive animals become a Patronus, for instance, Grindylows, Werewolves, or Trolls?

What Are They Made Of?

Harry Potter Casting A Patronus Charm

Many witches and wizards can generate Patronuses, but do they really know the exact mechanism of production? These "entities" look like they are made of some semi-transparent, glimmering-white or silver substance; could it be like ectoplasm?

Another point to note: given their material, are they able to pass through solid objects or traverse enormous distances? In other words, do they have a half-life, slowly degrading over time, or can their effects last indefinitely?

How Do They Defeat Dementors?

The only spell that can fight off an attack by the Dementors of Azkaban is dragging one's most pleasant memories into the forefront of the mind, using them to charge the body's magical energy, and casting it from the wand with the incantation (verbal or otherwise.)

But how exactly does this action affect these fiendish things whose diet consists entirely of hope and joy, the same emotions that a Patronus is based on? Maybe they hate it because it's too much of a good thing, like muggles overeating junk food or drinking way too much soda.

Are They Really That Hard To Learn?

On several occasions, characters have tried to explain how the level required to learn this spell is super advanced, greater than what is necessary to pass the N.E.W.T. exams in the seventh year. Harry Potter learns it in his third year, with the help of an accomplished trainer, but a thirteen-year-old child shouldn't technically be able to produce a Patronus so nonchalantly.

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Two years later, under Harry's haphazard tutelage, a number of students in Dumbledore's Army also pick up the skill surprisingly quickly. There is no consistency between plotlines here.

How Can Evil People Cast Them?

In a surprising narrative twist, readers/audiences are shown Dolores Umbridge, a witch whose malice could outshine that of Lord Voldemort's at times, with a sparkly Cat Patronus (because of her affiliation with anything feline.)

Simultaneously, the community believes that people with darkness in their souls are strictly unable to produce anything close to one — a theory that's not fully tested, though, because evil wizards often prefer the company of Dementors and other cursed creepy crawlies that populate the stories, so why would they care about Expecto Patronum?

What Are The Different Things They Can Do?

Dumbledore's Patronus, although not included in the movies, and he has been shown using it to convey top secret messages from place to another. It also transmits voice-notes, to put it bluntly, and are far too slippery to be caught (if there even is a way to do so.)

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Professor McGonagall's employs her cat to inform the other professors when she discovers that Harry has snuck into the castle. Further, she can generate three Patronuses simultaneously, which raises another query: can they each perform a different task?

Chocolate & Patronuses

Remus Lupin feeds Harry a bit of chocolate after his horrifying Dementor experience aboard the Hogwarts Express, claiming that it would help him feel better, which it actually does (spreading a sudden "warmth to the tips of his fingers

and toes.")

This is a complete mystery, because how can a cacao bean extract stave off Dementor darkness, but more so because chocolate is a decidedly non-magical product. Unless it isn't, and there is a connection between it and the Patronus Charm.

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