This is actually very closely related to a thread from last month, which featured banishments native to LotR, Pokemon, and, er, Wicca. In that thread, we read the 'proper combination' (ie, PPC standard) as modelled on the Bell-Book-Candle method of traditional Catholic exorcisms, but modified to invoke canon, rather than God. We then assumed that the same would work for other canons - take a canonical banishment method, and adapt it to protect canon.

I think using Expecto Patronum to banish a wraith falls into the same category. It's a canonical wraith-banisher, after all. But if you just use EP, then you have to explain why a character in the story casting it doesn't have the same effect.

I suppose it could be that PPC Agents' patronae (?) act against canon-unfriendliness, while canon characters' don't... but I think it'd be more fun to modify things slightly. So, what does a Patronus Charm look like? According to the HP wiki:

To successfully cast the spell, one must muster the happiest memory they can think of (the happier the memory, the better the charm will work) and 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 will come from the tip of the wand and can be directed towards a target by pointing one's wand at said target.

Assuming we don't want to alter the words of the spell, that gives us two things we can change: the memory, and the 'drawing circles'. The first is easy - rather than a happy memory, require the agent to concentrate hard on remembering the canon. Then, either keep the circles - or require them to draw something related to the canon.

And remember, this isn't something that can only take place in HP-verse; we use neuralysers outside Men In Black, don't we? So let's decontextualise it a little...

---

"Keep him steady!"

"That's not as easy as you make it sound!" Freckles called back, leaping over a fallen tree. Frodo was barely three paces behind her. "Why couldn't we have had a normal mission, huh?" she demanded. "One where Frodo's a wuss, not a psychop-eek!" She dodged around the hobbit's attempted decapitation, curved around a bramble thicket, and headed back towards her partner. "Get a move on!"

Sandra closed her eyes, focussing on the images that were by now burned into her brain: Frodo Baggins sitting under a tree, book in hand, glancing up as he heard Gandalf approaching. After watching the movie so many times, the memory was as vivid as reality: the green of the leaves, the softness of the grass, the incredible blue of Frodo's eyes.

"Expecto Patronum," she murmured, raising her wand - actually a miniature version of Gandalf's staff - and sketching a five-pointed star in the air. "Expecto Patronum..."

Freckles screamed, only a few yards away, and Sandra's eyes snapped open. "Expecto Patronum!"

A burning white shaft of light burst from her wand, lancing past Freckles and striking the ground in front of Psycho!Frodo. Out of that electric glow leapt the blazing form of her Patronus, and Frodo had no time to run.

The wraith was hurled out of Frodo, flying backwards across the clearing, and passed through half a dozen trees before it had time to recover. It swirled back towards its victim, desperate to regain its host - and completely missed Freckles leaping in from the side, jar in hand.

Holding the trapped wraith up, Freckles glared at her partner. "Two things," she said.

"Go on."

"One: never do that to me again. And two: your Patronus is a squirrel?"

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... I think there might be a 'Sandra and Freckles Experiment With Exorcisms' story in the works, I'm having far too much fun with this.

hS

(Also, the spell is Expecto Patronum. Just for future reference.)

After all, exorcisms in the PPC are pretty much "whatever gets the job done". We have a "proper" combination (light, loud sound, circle and source of canon), but it doesn't get used every time.

A Patronus would be a pretty good source of light, too, so it can even fit into the "proper" exorcism!