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THERMOS!, or, How a Muggle-Born Brought a New Age of Spell-Making to Hogwarts (Entirely by Accident)

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Phoebe McDevitt struggled to keep her eyes open as Professor Binns continued to prattle on and on about... something relating to vampires and their fight with a "lethifold," whatever that was. In the years since Harry Potter had left Hogwarts, no one had bothered to exorcise the ghostly teacher, which was a major disappointment. Before she'd come to Hogwarts, Phoebe had liked history well enough, and was ecstatic when she'd first found out about the History of Magic class. Her joy was short-lived. Specifically, she was pretty sure it died within two minutes of Professor Binns opening his stupid transparent mouth on the first day of class. Now she was in her fifth year, and she'd spent the whole time staring out the window, longing for lunchtime. 

Absentmindedly, she reached into her bag for a perfectly ordinary Muggle thermos, which she'd brought with her from home. Really, she doubted she was the first Muggle-born to think of it, though she never did see any others around. Maybe wizards had already invented something similar. Either way, the Muggle thermos worked just as well, and it made no sense to buy a magical one when she already had one. Phoebe took a sip of some pumpkin tea, which had been at breakfast. Ah, still just as good as it had been that morning. The House Elves really did have that special touch.

"Psst," someone whispered. It was her friend, Titus Midgeon, another Slytherin fifth-year. "Can I have a sip?"

Phoebe nodded, passing the thermos to Titus. He took a swig of the pumpkin tea, eyebrows jumping in surprise. Phoebe gave him a quizzical look as he handed the thermos back to her, but he simply motioned to Binns, as if to say, "I'll explain later."


"I was surprised the tea was still hot," Titus said to Phoebe as they made their way down the stairs from History of Magic to the Great Hall for lunch. "Breakfast was hours ago. What spell did you use for that? I may want it..."

Phoebe gave him a look. "Titus, it's just a thermos. It barely cost seven pounds."

"...What?" He was giving her a very blank look.

Phoebe had to smile. He was very clever, but when it came to Muggle things, he could be a bit, well... clueless. Hogwarts and the rest of the wizarding world had changed a lot since the fall of Voldemort, and people in general were much more accepting of Muggles and Muggle-borns, but they still knew nothing about the terminology or culture. Unless, of course, they took Muggle studies, which Phoebe did, mainly because she figured it'd be an easy O, which it was. Although she'd gotten some points knocked off her essay about "why Muggles need electricity." The professor had required at least three feet of parchment, but Phoebe, who'd never seen any benefit in dilly-dallying to the point, had only written a single line, and handed that in.

Because they don't have magic.

To which the professor had replied, "Okay, so you're not wrong..."

She'd still gotten a passing grade, though.

"Thermos," she repeated. "Keeps liquids warm all day. Very useful. I could probably get you one, if you like." She'd just ask Mum to send one up with her next letter.

Titus (who didn't take Muggle studies, despite Phoebe begging him to, both to be in the same class as her friend, but also for the sake of her sanity) didn't look like he quite understood, and was clearly still thinking as he and Phoebe made their way to the Slytherin table. As Phoebe began to pile her plate up with food, he pulled out his wand, and pointed it at his cup, which he'd filled with hot chocolate, and bellowed, "THERMOS!"

Phoebe immediately began to crack up. Titus, not one to be swayed by other people's doubts, brought the mug with him to his next class, making a great effort not to let a single drop spill. Phoebe couldn't help but snicker at him, and she wasn't the only one.

They all stopped laughing when, hours later, Titus stumbled and spilled some of the hot chocolate all over himself, and let out a catlike screech - because the hot chocolate was still, in fact, hot.


By the end of the day, Titus and Phoebe had been asked by no less than fifteen people to teach them "that spell you used to keep your drinks warm."

"It's just a thermos!" Phoebe said, somewhat exasperated already, when a mousy little Ravenclaw asked her at dinnertime.

"You just point your wand and say 'THERMOS!'" said Titus, who had a dull brown stain on his white shirt, and hadn't bothered to go up to the dorm to change. Phoebe wondered if pointing at the stain with her wand and saying "OXY-CLEAN!" would help, but she didn't try it.

By the end of dinner, it had spread like a tidal wave across the Great Hall, Purebloods (and a couple somewhat amused Muggle-borns and Half-bloods) pointing their wands at their cups and yelling, "THERMOS!", determined that they would have hot cocoa at bedtime tonight.

From the Slytherin table, Phoebe wondered what sort of monster she'd created.

From the teachers' table, Headmistress McGonagall wondered if maybe Hogwarts should introduce some cups with lids.


"So, you're the famous spell-maker," James Potter said, grinning as he moved to sit with Phoebe by the lake. He was younger than her by two years, and was in Gryffindor, but the two were still pretty friendly - they were, after all, both in dueling club, and James never seemed to mind practicing with her.

"It was Titus that figured it out," Phoebe reminded him, moving her bag to make room for him.

"Yeah, but you're the one that told him how to do it."

"I never told him to do anything. He just assumed, and he just so happened to be right."

"Doesn't seem to matter to most people," said James. "Most people seem to think you're some kind of genius."

Phoebe pretended to glare at him. "Are you saying I'm not some kind of genius?"

James didn't answer the question, going on to say, "I wonder if that'd work for anything else. I mean - would pointing a wand at something and shouting some Muggle word at it actually work, or was it just a coincidence?"

Phoebe shrugged. "Not sure," she admitted. "I did kind of wonder that."

"Have you tried it with anything else?"


"Well, why don't you?"

She gave it some thought. "I don't know. Why don't I?" She rummaged in her bag for some parchment, setting it on her lap. Grabbing her wand, she hesitated, before pointing it at the parchment. "NOTEBOOK!" she shouted, feeling a bit stupid.

There was split second of stillness, before the parchment began to ruffle, rearranging itself into a small booklet. Within ten seconds, the parchment had fashioned itself into a small pocket notebook. Phoebe and James simply sat there, staring at it like they expected it to explode, before finally, James said something.

"Wow. So. That just happened."

Phoebe reached for the notebook, flipping through it. It didn't look like the spiral-bound ones she'd used in Muggle school - the paper was yellowish, not white, and there were no lines on it, but it seemed to be a perfectly suitable notebook. "I wonder if you could modify this with other spells," she said, thinking aloud. "You know, make it so the pages never ran out, make it so the pages never tore, that sort of thing. I'll have to do more poking around to find that out."

"Still, that's not half-bad for a first try," James said.

"No," she agreed, "that's not bad at all."

"Now," James said, reaching into his own bag for some parchment, "you mind if I steal that spell and use it myself? I swear, carrying parchment around is such a pain. Just today I had to stop and un-shuffle things because my History of Magic homework had gotten mixed in with my Ancient Ruins homework..."


The notebook spell spread even faster than the thermos spell, which wasn't surprising as organized notes were generally more useful than hot cocoa. It didn't take long for Phoebe's fellow Muggle-borns to catch on as to how these spells were created, and soon, a spell-making craze had gripped Hogwarts. Results varied. A lot.

Carmen Morales successfully Transfigured a couple quills and bottles of ink into ballpoint pens. ("Wouldn't it be cheaper to just buy some ballpoint pens?" someone had asked, though they were still getting out their own quills and ink to try it.)

Lucy Weasley, a Half-blood, figured out how to bring Muggle sports to Hogwarts, using some Quidditch equipment, some rocks, and some very choice words for a particularly unruly Bludger. ("OH, JUST BE A FOOTBALL, YOU STUPID GLORIFIED CANNONBALL!")

Naomi Zimmerman's spell, "SHIN-GUARDS, SHOULDER PADS, AND CLEATS!", was a bit of a mouthful, but casting it on your Quidditch robes worked wonders, giving them the same protective qualities as an American football player's uniform, without all the bulk, and even made taking a Bludger to the back more bearable than it had been before. ("Isn't that sort of cheating?" "Call it what you want, just be glad it works. Honestly, the lack of safety measures at this school are appalling...")

Victor Pembleton, on the other hand, had caused more than his fair share of trouble when his attempt to turn an ordinary book into a Kindle resulted in the book launching itself into the fireplace and bursting into flames. ("What did you expect? You know electricity doesn't work at Hogwarts!")

Phoebe herself invented several spells over the weeks. She managed to turn ordinary papers into maps, and she gave a broken Snitch the same function as a compass. "It begins glowing when you're facing North!" she explained.

She also managed to teach a Remembrall how to actually tell you what it was you've forgotten. "It's like a Muggle planner - you tell it everything you need to remember. When you rub it, it repeats the list back to you."

Her most impressive accomplishment thus far was when she even managed to get a wizarding radio to pick up Muggle stations nearby. It was that little exploit that finally got the Headmistress to ask to see her after class one day.

"Am I in trouble?" Phoebe asked, sitting down in front of McGonagall's desk. The Muggle studies professor, Rothbart Spectre, was there as well.

"No, Miss McDevitt, you are not," McGonagall assured her. "We've just heard about this... trend you've started. Of new spells used to make wizarding objects more like Muggle ones."

"Is that against the rules?" Phoebe asked, immediately on the defense.

"No," Professor Spectre acknowledged. "Mainly because we never thought we'd actually need a rule against it..." he added under his breath.

"We just want to ask you to promise you won't do anything dangerous with your spell-making," McGonagall said. "You have a history of getting into trouble--"

"That portrait had it coming!"

"--not to mention causing ruckus in the corridor--"

"Peeves cast the first spell! I merely acted in self defense!"

"--and we'd like your word that you won't act irresponsibly."

"Are you giving every student this lecture?"

McGonagall gave her a very stern look over the top of her glasses. Phoebe immediately shut up, shrinking back into her chair.

"We are singling you out, Miss McDevitt," she said firmly, "because as the spearhead of this whole thing, others may look to you for an example. As Professor Spectre said, there are no rules to limit spell-creating at Hogwarts, so if you caused trouble, there'd be no orthodox way to punish you. So I need your word. If you break it, I trust you understand there will be consequences."

"Yes, Professor," Phoebe said, "I promise. I'm just trying things out and seeing what works. I'm not interested in doing anything stupid."

"Good. I was hoping you'd say that."

"Besides," she added, feeling a bit braver, "trying to transfigure a wand into a gun didn't work, anyway."

McGonagall glared at her, and Phoebe decided maybe she wasn't feeling that brave.

"I'm kidding," she said. (She wasn't.)

McGonagall didn't look like she believed her, but apparently decided to let it drop. Instead, she said, "I would like you to know that I'm very impressed with what you've done. Creating a spell at your age is a very big accomplishment, one you should be very proud of."

Phoebe smiled at actually receiving some praise from the Headmistress, but said, "Titus was the one that created the thermos spell. I only gave him the idea to try it."

"But you've created some spells on your own, haven't you?"

"Well, yes."

"How many?"

Phoebe hesitated. "...Eleven."

"Eleven?" Now McGonagall seemed genuinely impressed. 

"Actually, Professor Spectre, I've been meaning to ask you--" Phoebe turned to the Muggle Studies teacher. "I was thinking, maybe I should write an article about all this. About the new spells, I mean. See if anyone's interested in printing it. People might find this useful, is all. Do you think anyone would take it?"

"I think several papers would take it," Rothbart said. "You should try to write something. I can help you, if you need it."

"Okay, okay, I will." She smiled to herself. "Thanks."

"That will be all, Miss McDevitt," McGongall said. "You may go. And remember what you promised."

"I'll remember," Phoebe said, standing up and collecting her bag. She headed for the door, then stopped, and turned back to Spectre. "Hey, Professor, do you think I could get some extra credit if I actually manage to publish an article someplace?"

Rothbart rolled his eyes. "Fine," he said. "But the Quibbler doesn't count!"


"What about House poi--"

"Miss McDevitt," McGonagall warned. "Go."

"Okay, okay, I won't push my luck." She began to leave again, then thought of something else.  "...Hey, Professor Spectre, how does it feel to know your laziest student has created eleven new spells practically by accident?"

"GO!" both professors shouted at once.

Phoebe decided she was done messing with her professor for the day, and quickly left before McGongall changed her mind about her not being in trouble for anything, snickering all the way.


"Ron, look at this--" Hermione slid her copy of the Daily Prophet across the table to her husband. "Some Muggle-born at Hogwarts has created a whole slew of new spells, she's not even taken her OWLs yet. Wrote this article about her findings."

Ron glanced at the article. "Phoebe McDevitt? The name sounds kind of familiar... maybe one of Harry's kids knows her."

"Maybe," Hermione shrugged. "It's quite an impressive accomplishment, though, isn't it? She's fifteen and inventing new spells. Most spell-makers are at least middle-aged before they manage to create a spell that actually works. I can't think of anyone else that managed it this young, except maybe Snape."

"I thought I told you never to invoke that name in my own home," he said dully. 

Hermione rolled her eyes, but she was smiling. "If it makes you feel any better, I'm pretty sure he was sixteen or seventeen when he created his spells. So she's one-up on him on the age front."

"Good. I don't care if he's dead, I won't stand to hear him praised in any capacity." Ron gave the article a closer look. "...What's a thermos?"

Hermione suddenly felt Phoebe's pain, and vaguely wondered if there was some way she could create a telephone. She never admitted it to Ron, but she spent many wasted hours that night trying to do just that, to no avail. It seemed, just as she suspected, that magic still couldn't work with anything electrical. At least, not yet.

Still, Phoebe's findings were slowly but surely helping to pull the wizarding world out of the Bronze age. Only two weeks after her article was published, a wizard in Dublin created a mirror that not only talked, but could be folded up and kept in someone's pocket. He called it "the easily foldable and transportable reflective device," or, the EFTRD for short. This was very impressive to Purebloods, but somewhat exasperating for Muggle-borns, who simply said that Muggles had had those for ages, and furthermore, that they usually just called them "compact mirrors." Not that anyone cared how Muggles usually did things.

The spell-making craze had officially left Hogwarts, and in terms of wizarding technology, after years of being stagnant, things were finally picking up.


Phoebe McDevitt herself went on to invent many more spells, after inadvertently helping to create the first batch. They began calling it "the next generation of spell-making." She became very respected in her field, becoming the first Muggle-born Slytherin to achieve any widespread recognition in the wizarding world. A few years after graduating, she finally told her parents about the whole thing. Phoebe hadn't intended to keep it from them or anything, she just wasn't sure how to bring up the fact that she'd accidentally revolutionized the spell-making field. But, eventually, she told them, and they took it well. Mrs. McDevitt said she always knew Phoebe would help improve the world, while her father simply seemed to find the whole story incredibly funny. They were both very pleased to hear she'd been awarded an Order of Merlin, Third Class. Whatever that was. 

Phoebe lived a very full life, publishing papers about her research, which was mostly bullshit - her primary way of discovering new spells was to point her wand at things and yell "MP3 PLAYER!" or "VIBRATOR!" or whatever, until something worked. But who needed to know those petty details? It was only a matter of time, everyone said, before she and her colleagues figured out how to make electrical items work with magic, too. She also became a professor at Hogwarts, as well as Head of Slytherin House. Indeed, life worked out very nicely for Phoebe McDevitt, and she carved out a nice little niche for herself in history, which, really, was all she'd ever wanted.

All because Pureblood wizards never figured out how to invent a fucking thermos.