I just recently finished watching Stranger Things with my dad. Almost immediately after, I got this ridiculous idea for a story, so I decided to put it down. Hope you enjoy!

Disclaimer: I don't own anything that doesn't belong to me.

…

"And that, students, is how you could – – theoretically – – build a particle accelerator in your basement, in the unlikely event that you should ever need one for some reason," Scott Clarke, science teacher at Hawkins Middle School, concluded. Finishing his lecture, he stepped away from the insanely detailed diagram he had made on his blackboard while assiduously not looking at five particular students sitting next to each other in the middle of the room, taking notes with far more fervor than any of their fellow classmates. "And with that lesson concluded, I believe it's time for today's test. I hope you all studied!" A chorus of groans from his students told him all too well which of them had and which of them had not.

Two of the aforementioned five students, Mike Wheeler and El Byers, stiffened. "Oh no," Michael whispered. "We completely forgot!"

Their three friends, Dustin Henderson, Lucas Sinclair, and Will Byers (El's brother, by adoption), regarded the other two in disbelief. "Seriously?! How could you two forget?! You said you were going to have a study session at your house last night after our strategy meeting!" Lucas asked incredulously.

"And one without us, too," Will added, looking hurt.

El looked down at her desk, ashamed. "Sorry," she muttered.

"Hey, it's not her fault," Mike said quickly. "We totally were going to study, but… We, ah… Got distracted…"

Dustin regarded the two with a knowing look on his face. "You two spent the whole evening making out, didn't you?"

Mike and El turned bright red. "N-no, of course not! Don't be ridiculous!" Mike protested.

"Friends don't lie," El reprimanded Mike sharply.

Mike winced, then sighed and reluctantly said, "Okay, yeah, we were going to study, but… Well…"

"You decided to study each other," Lucas said, looking disgusted.

"Pretty much, yeah," Mike confessed, looking embarrassed.

"Was fun," El said shyly, shooting a quick smile at Mike, who smiled back.

"Mike, could you please not talk about kissing my sister? It makes me feel sick," Will complained. There was a pause. "No, wait, I think I actually am about to-" He coughed and suddenly spat up an eerie black slug.

Everyone stared at the slimy creature that didn't quite look like it belonged in this world with morbid fascination. "You know, you really should see a doctor about that," Mike commented.

"Mike, what doctor in the entire world could possibly help in this situation that wouldn't drag Will or El off to some shady government facility, never to be seen again?" Lucas pointed out.

"Fair enough," Mike conceded.

"Don't like doctors," El whimpered.

"Oh, by the way, Lucas? Pay up," Dustin told the boy next to him, extending a hand. Lucas grumbled and stuffed a crumpled five dollar bill in the outstretched palm.

"What's that about?" Will asked.

"Oh, I bet Lucas that Mike and El would be completely unprepared for the test because they spent all evening making out with each other. He was certain that wasn't going to happen. As you can see, I won," Dustin said smugly.

"I really need to stop making bets with you. I always lose," Lucas complained. "It's uncanny!"

Mike groaned and put his face in his hands. "Could you please stop making bets about what my girlfriend and I do in our free time? It's kind of embarrassing."

"Especially when said girlfriend is my sister," Will added.

"I'll stop making bets when Lucas stops being wrong about everything," Dustin said cheerfully.

"One of these days…" Lucas growled.

"All right, class," said Mr. Clarke, who had just finished putting the test sheets on his desk. "Come up and take your tests one at a time, please. And remember, this grade will count for a significant portion of your final-"

Without warning, the windows shattered as heavily armed and armored soldiers smashed through them. The door was knocked off its hinges as more soldiers rushed in from the hallway outside, and the classroom suddenly grew very cramped with all the military enforcers jockeying for space between the desks and students, who looked more…irritated and resigned than afraid.

"FREEZE! NOBODY MOVE!" one of the soldiers shouted, brandishing his gun menacingly.

"Oh for…seriously?! This is the fifth time this month!" Mr. Clarke protested, looking far less afraid than most people who had several guns shoved in their faces would normally be.

"WE ARE HERE FOR SUBJECT ELEVEN! SURRENDER HER NOW, AND NOBODY NEEDS TO GET…WHAT THE FUCK DO YOU THINK YOU'RE DOING?! I SAID NOBODY MOVE!" the leader of the soldiers shouted at Lucas, who was in the process of handing a five-dollar bill to Dustin.

"Sorry sir, but my friend here owed me money. You see, I bet him that you guys would show up today, and he was positive that you wouldn't! Naturally, he was wrong," Dustin said cheerfully.

"How the hell did you know?! Seriously, how?!" Lucas demanded.

"You knew that we were coming?! WHO TOLD YOU?!" The (presumably) lead soldier demanded, sticking his gun in Dustin's face.

"Nobody, Sir, I just had a good feeling," Dustin said, not looking particularly bothered by the deadly weapon pointed at him.

"A feeling? Sir, maybe he's psychic too! We should take him in for questioning!" One of the other soldiers suggested, voice filled with awe.

"Excellent idea, soldier! Boy, you're coming with us!" The lead soldier barked.

Abruptly, Will spat up another slug. "Excuse me," he said apologetically.

"… And you're coming with us too!" The head soldier declared. "I have no idea what's up with you, but it's clearly not normal!"

"Sorry, but I don't think that's going to happen," Mike said, glaring at the soldier.

"Oh yeah? And what makes you say that, smart guy?!" The head soldier demanded, pointing his gun in Mike's face.

"Because the girl you're looking for is an incredibly powerful psychic who can murder people with her mind and is extremely protective of her boyfriend, whom you're pointing a gun at?" Dustin suggested cheerfully.

"And by extremely he means scary protective. They had to transfer Troy to a school in another town to keep El from breaking any more of his limbs or causing him to wet himself," Lucas added.

The lead soldier glanced at El, who was looking at him with an expression of pure hatred, blood oozing from her left nostril. "Mouth breathers," she snarled. "Bad men!"

"Oh, shit-" the lead soldier managed to get out before he and all the other soldiers collapsed, blood oozing from every orifice. Given that a great number of them landed on top of desks or students, that blood got all over the place, and quite a number of El's classmates made their displeasure of this very clear.

"Come on, I just got this thing dry cleaned," one boy complained, looking down at his blood-spattered pants.

"I was going to wear this to my date tonight! Now it's ruined! Ruined!" A girl shrieked, gesturing dramatically at her blouse.

"Ack, one of them fell on me!" a boy yelled. "Geez, what do they feed these guys, he's really heavy!"

"You have no right to complain, two fell on me!" the kid next to him griped.

"Sorry," El apologized. She looked at Mike in concern. "You okay?"

"Yeah, I've gotten used to having guns pointed my face by now," Mike reassured her.

"We should probably be more concerned about how desensitized we've gotten to that, really," Will commented.

"What I'm more concerned about is that, despite sending like two dozen or more squads our way by now, not only are they not giving up, but they STILL haven't provided any of the troops with a way to protect against El's powers," Lucas grunted, shoving a dead soldier off of his lap.

"Well, that's the government for you," Mr. Clarke groused, looking at the blood covering the floor in frustration. It'd just been waxed this morning. "Why bother admitting you've made a mistake when you can keep funneling millions and millions of taxpayer dollars into increasingly pointless and futile attempts to try and make it look like that mistake never happened?"

The first time this had happened, it was horrifying. The second time, disturbing. The third, somewhat alarming. After that, however, it had just gotten somewhat irritating. It was amazing, he thought, the sorts of things a person could get used to.

Sighing, he clapped his hands together. "Well, students, it looks like our test will have to be postponed until tomorrow." He tried to pretend he didn't hear the audible sigh of relief that filled the classroom. "However, as usual, anyone who is willing to help me clean up this mess and deal with the bodies will receive extra credit on their final grade."

"Sheriff Hopper will probably be happy to get more military hardware for the police armory," Mike said as he pushed a soldier off his desk. "It'll be useful if the government decides to give up on secrecy and flat-out invades the town. There's only so much El can manage, even if she is growing stronger every day."

"Sorry," El said apologetically.

"It's not your fault, El. We can't rely on you to do everything. We have to do our part too," Mike reassured her.

"And in the meantime, we're going to get more 'mystery meat' for lunch this week!" Dustin said eagerly.

"Not that it's much of a mystery, since pretty much the whole school knows by now it's human flesh," Will commented.

"Should we be concerned that by this point, we're more or less totally okay with being cannibals?" Lucas wondered.

"To be fair, it's probably still healthier than what they used to put in the lunchmeat," Mike pointed out. His friends had no choice but to agree with this.

"Would rather eat Eggos," El grunted.

Before anyone could get out of their seats to deal with the messy (and by this point, far too familiar) process of disposing of dead bodies, the lights started to flicker, the room shook, and a massive crack ran up one wall. "Oh come on! Again?!" Mr. Clarke snapped in frustration.

Dustin extended a hand. "Pay up."

"Dammit! How do you always know?!" Lucas yelled angrily, handing over another five dollar bill.

"Maybe he really is psychic," Will suggested. "He usually does seem to be right about everything."

Dustin shrugged. "It's a gift."

With an eerie, whistling shriek, a pale, slender, faceless abomination started to pull itself out of the wall, the front of its head splitting open like a tooth-edged flower to reveal a deep gaping maw-

And an annoyed El pointed a hand at it and shouted, "NO."

The monster promptly disintegrated into specks of black dust. The lights flickered a few more times, then shone steadily again. The hole in the wall, and any trace the creature had ever been there, were gone.

"You okay?" Mike asked in concern, quickly handing El a tissue so she could wipe away the blood dripping from her nose.

She nodded, her face a bit pale and drawn but otherwise alright. "I'm fine. Gets easier every time."

"Which is a good thing, we don't want to have to spend another year with Lover-boy here pining for you and thinking you're dead," Lucas joked.

"I wasn't pining," Mike protested. Absolutely nobody believed him.

"Thank you for dealing with that, El," Mr. Clarke said, completely unfazed by the interdimensional horror that had tried to burst into their reality only to be immediately vanquished. "I don't suppose the next time, you can obliterate it a little less… Completely? If we could actually get an intact dead body from one of those things, I'm sure we can learn a lot more about them."

"I'll try," El promised.

"All right. Now, like I said, class, let's get these bodies out of here-" Mr. Clarke began when suddenly, the light started flickering again ". He frowned, actually surprised. "Another one? So soon? That's…"

The five friends in the middle of the room exchanged horrified looks. "Oh no," Will whispered. Dustin extended a hand to Lucas, who uttered a word he probably shouldn't have known before giving him another five dollar bill.

"Oh no? I don't like the sound of 'oh no.' What's happening?" Mr. Clarke asked sharply. If his ace students and budding young paranormal researchers and monster fighters reacted like that, that meant something REALLY that was about to happen.

"Mr. Clarke, you remember how we called you last night to ask, theoretically, how to build a particle accelerator in our basement?" Mike asked nervously.

"I do, yes," Mr. Clark said warily. It was hard to forget, especially since it had interrupted him in the middle of date night. Somehow, they always called on date night. It was uncanny.

"And no matter how many times we asked, you insisted that we would have to wait until today to learn about it?" Mike continued.

Mr. Clarke's heart sank as a deep sense of dread filled him. "Yes…"

Will swallowed, then coughed as he spat up another slug. "Well, um, we didn't theoretically need to build a particle accelerator in our basement, we actually needed to."

"… WHY DIDN'T YOU TELL ME THAT LAST NIGHT?!" Mr. Clarke demanded.

"Because you told us that you don't want your date nights ruined by knowledge of just what sort of horrible supernatural interdimensional abominations we're using your scientific knowledge to combat?" Dustin reminded the teacher.

"… Oh. Right. I did say that, didn't I?" Mr. Clarke recalled, his face drooping. He sighed. "I just wanted a bit of separation between the craziness my working life has become and my personal life. Some 'me time.' Was that so wrong?"

"Apparently, yes," Lucas pointed out. Mr. Clarke groaned.

"We know we put a lot of pressure on you Mr. Clarke, but… Honestly, you're the only person who can help us with the sort of thing. It's not like the library could tell us half the stuff we need to know, especially at the hours we tend to operate at," Mike said apologetically.

"You're the best," El said helpfully.

"Well, it's nice to hear that I'm appreciated, at least," Mr. Clarke said, chuckling in self-deprecation. "Still, it'd be a lot easier on all of us if there were just some sort of… I dunno, free, universal resource for information on all walks of life that could be consulted at anytime from anywhere to solve just about any solution. Like… Some kind of… I dunno, super encyclopedia?"

"Probably could use a better name than that," Will said.

"That does sound pretty useful," Mike admitted.

"Nah, there's no way something like that'll ever happen," Lucas said dismissively.

Dustin extended a hand. "Five bucks that it will come into being on January 15, 2001."

Lucas snorted. "Considering that the world will probably end way before then? You're on!" He shook Dustin's hand, demonstrating an astounding lack of pattern recognition.

"So, what exactly are we up against this-" Mr. Clarke began, only for the room to suddenly shake so hard that some of the other students yelped in alarm and reflexively hid under their desks like they vaguely remembered those earthquake preparedness or Soviet bomb drill films told them to do. The lights flashed, then abruptly shattered, sparks showering on the class briefly before the whole room went dark, eliciting more screams.

Outside, the sky turned red and abruptly split open, vomiting nightmares onto the town of Hawkins, most prominent of which was an absolutely colossal many-limbed horror that defied description which landed with an Earth-shaking thud, emitting a soul-rending mind-breaking roar as it ponderously began to move, its massive appendages destroying buildings with every step, screams and explosions and monstrous howls echoing in the near distance.

Everyone in the classroom stared at the gargantuan monster in disbelief. A few crept right back under their desks, rationally knowing that there was no way hiding under their desk would possibly protect them from whatever that thing was, but figuring they'd rather hide under there than face it right now. "What in God's name is that thing?!" Mr. Clarke demanded finally.

"Yag-Thusogga, Defiler of Souls, Ravager of Civilizations, Devourer of Dimensions, and Destroyer of Worlds," Will recited. "Eighth of the 12 Lords of the plane we call the Upside-Down, come to 'flip' our realities so that its realm is 'right side up' and we fall into darkness and decay."

"Ah," Mr. Clark said vaguely. He glanced at the kids. "Can you stop it?"

El nodded and pointed the blackboard. Mr. Clarke's eyes lit up, understanding at once. "Okay, class, looks like we're canceling the planned test for today in favor of a more practical exam. Today we're going to see if we can build a working particle accelerator in the field. Succeed, and you will all receive passing grades. Fail, and we'll all probably die a horrible death. Fortunately, just about everything we need to build the device is right here in the school. So! Here's what we have to do…"