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Donnie's Devilish GED Prep Class

Summary:

Donnie takes his GED Prep Class--aka his brothers--to the Mystic Library for a field trip. The boys being the boys, Dewey Decimal math somehow escalates to demon summoning. The Devil seems interested in... ducks?

Notes:

The crossover nobody asked for. It's another random one-off story I came up with while doing writing prompts. It isn't nearly as polished as my multi-chapter fics, where I slave over every word and edit like crazy, but hopefully it's still enjoyable.

The prompt was "A book club accidently summons the Devil by reading from an old tome."

Work Text:

It had been a great idea. Donatello was, after all, a genius. All his ideas were great. When he had planned a return trip to the Mystic Library as part of his new efforts to force some formal education into his dumb-dumb brothers’ heads, the plan had many things to commend it. An atmosphere of scholarship. Textbooks on any and every topic covered by the American educational system. A journey to the Hidden City that could feasibly be described as a ‘field trip’—a thing his brothers had been requesting in increasingly obnoxious tones ever since he had declared Donnie’s Daring GED Prep Class mandatory.

What Donnie had—not forgotten, per se, considering his eidetic memory, but had at least overlooked—was that his brothers collectively had the attention span of a goldfish and, when bored, tended to mess with any shiny object within arm’s reach.

“What’s THIS?!” Michelangelo asked, holding up a cobweb-infested tome glowing with something that was the opposite of light. The area around the book was cast in shadows, and Donnie couldn’t resist lowering his goggles to get some readings.

“Lemme see that, Mikey!” Leonardo grabbed the book out of the youngest’s hands and examined the cover.

Raph leaned over his two shorter siblings, as easily distracted from Donnie’s lecture on the Dewey Decimal System as the others had been. “Isn’t that like… the evil symbol? You know, from Hot Topic?”

Donnie flipped his goggles back up. Whatever was coming off that book, it wasn’t something his sensors could pick up. He made a mental note to upgrade them when he got back to his lab. “Scoff. What you are referring to as ‘the evil symbol’ is known outside of Hot Topic as a pentagram, and it is the inversion of a pentacle, originally a symbol of the five virtues of Christ—”

His brothers completely ignored him. “Hey!” Leo called, “Raph is right! Maybe we can summon something spooky if we read it!” He cracked the book open to a random page. “Et proiectus est draco ille magnus serpens antiquus qui vocatur Diabolus et Satanas qui seducit universum orbem proiectus est in terram et angeli eius cum illo missi sunt…”

The absolutely butchered Latin grated against Donnie’s tympanum with a sound like Shredder set loose in Repo Mantis’s junkyard. “You speak SPANISH, Leo, how is your Latin pronunciation so bad?” He grabbed the book and shouldered his twin out of the way. “If we’re going to summon the Devil, we’re at least going to do it with reconstructed Classical vowels.”

Leo cocked a hip, tossing his mask tails over his shoulder. “If you think you can do a better job, mi hermano, I’m all ears.”

Donatello had learned three kinds of Latin before the rest of them had learned how to read English, and now was the time to prove it. He picked up the recitation at the top of the verse. “Et proiectus est draco ille magnus serpens antiquus…”

A symbol appeared along the floor of the reading room, a five-pointed star etched into the hardwood with something that burned. Donnie kept reading, but caught the scent of sulfur, suggesting that it was probably brimstone.

“Oh me gosh, he’s actually doing it!” Mikey shouted, hands thrown against his cheeks. Not for the first time that day, Donnie was glad he had requested a private study room, one soundproofed from the rest of the library.

“He is doing a better job, Leo. Admit it,” Raph rumbled.

“I admit nothing.”

‘—yet,’ Donnie mentally tacked to the end of Leo’s statement. Donnie was every bit as good with languages as his twin—he just happened to prefer dead ones. Leo always said dead languages were useless, but he was going to eat his stupid words when this summoning succeeded.

Mikey dropped his hands and glanced nervously at what had developed into a full-on summoning circle, a shadowy ring having grown up around the star. “Are we sure this is a good idea?”

Just then, there was a crack like the sound of a whip, and a pillar of smoke billowed up from the center of the circle. “Who dares to summon me?” asked a voice that was soft as a weighted blanket and as hard as titanium alloy.

Leo donned a shit-eating grin that couldn’t mean anything good. “Sorry, new phone. Who dis?”

Donnie leaned over and whacked Leo on the head with the book.

“Ugh,” The smoke dissipated into nothing, leaving behind a short blonde man in a top hat and tailcoat. Emotion rolled off him in waves—enough that even Donnie could feel it—but it was less ‘demonic fury’ and more ‘beleaguered irritation.’ It was a common reaction to dealing with Leonardo, so Donnie didn’t blame him.

“You read the verses,” he swung about a cane with an apple on the top, pointing it at Leo. “You should already know.” He raised a perfect golden eyebrow. “That is, unless you were empty-headed enough to read a bunch of Latin out of an obviously cursed book without knowing what it meant.”

“Nahhhhhhh,” Leo flapped a hand dismissively before pulling it up to shield his mouth from the demonic presence. “What did we read, ‘Tello?”

Donnie slammed a palm against his forehead. The whisper-shout had been plenty loud enough for their guest to hear. “It was a verse from Revelations, dumb-dumb.” When Leo continued to stare blankly, Donnie groaned, deciding to get the point across in a language Leo would understand. “He’s the Devil. You know, from the Bible?”

“Oh!” Leo’s smile didn’t waver. “Good thing we weren’t planning on defeating him with the power of friendship or whatever.”

The gentleman in the center of the circle cleared his throat. “Yes, well, as fun as it is to be summoned on accident for the 4,872 time, I was rather busy before this. If you kids could get on with a dismissal...” He trailed off.

Mikey popped back out of his shell, though he remained cradled in Raph’s arms. “Wait. Are you not freaked out by…” he waved his green, 3-fingered hands in a vague gesture that encompassed his entire body and possibly Raph’s, “this whole situation?”

Raph frowned, brow ridges furrowing. “I’m sure they’ve got weirder stuff in… wherever the Devil comes from.”

Donnie pinched the top ridge of his snout, feeling a Raph-chasm of his own forming. “Hell. The Devil is the ruler of Hell. HOW could you NOT KNOW THIS?” He was going to have to design a unit called ‘The Impact of Christianity on Western Culture.’ He hated to spend too much time on the humanities when he could be teaching STEM subjects, but clearly, it was needed.

The Devil spun his cane before planting one end against the floor and leaning on it. “I suppose it is odd to see turtle folk on Earth, now that you mention it.” A strange glint entered his eyes, and the Devil leaned forward, close to the molten lines of the pentagram. “Are there duck people too? I know they certainly weren’t part of the original design, but,” he placed a delicate hand on his chin, “neither were turtle people as far as I know.”

“Raph… doesn’t know?” He shrank back just a hair when the Devil turned to look at him. “What? There are lots of kinds of yokai and mutants and Raph hasn’t met all of them!”

The Devil frowned and leaned back, recentering himself in the summoning circle as the brief light of interest left his eyes. “Well. Like I said, I’m a busy guy. Ask your question so we can all get back to living our lives.”

“A question?” Donnie felt his curiosity flare like a fire in his synapses. “You mean the nature of this summoning forces you to answer a question? And possibly compels truth?”

The Devil nodded, his enormous hat bobbing with the motion but staying on top of his head. “Indeed. Shall we get this over with?” He raised a hand to examine his nails… claws? They seemed more like claws.

Donnie held in a mad cackle as the implications hit him. He could ask about antimatter. He could ask about the size of the universe. He could ask for the fucking theoretical model for turbulent flow. Donnie didn’t know, theologically speaking, whether the Devil was supposed to be omniscient, but based on what the gentleman had been saying, the Devil was older than the universe. Donnie’s blood pumped excitement through his veins like he had opened a shoddily wrapped Christmas present to find a lump of uranium inside.

Which question to ask, though? It seemed they would only get one, so Donnie would have to make it count. He would make a prioritized list, with questions ranked based on difficulty, relevance to engineering, and—

“Where do turtles go?” Leo asked into the momentary pause. Donatello reconsidered the practical merits of murdering his twin for what was not the first and would not be the last time.

“What?” the Devil looked up from his claws, his cherubic face squished into bafflement.

“You know,” Leo clarified in an infuriatingly disinterested tone, “all dogs go to heaven. Where do turtles go?”

“Ooooo!” Mikey threw his arms wide with enthusiasm, all youngest charm that Donnie refused to succumb to. “That’s a good one, Leo!”

Raph ignored Mikey’s wriggling, continuing to hold him steady. “Oh, yeah! Like that movie we watched when we were younger!”

“If this is torture, chain me to the wall!” Raph and Leo recited in unison.

Raph worried his snaggle-tooth with his tongue, the snapper’s version of contemplative. “Actually, Raph never really got what that line was about. Maybe we should have asked—”

“Oh, I’ll explain that one when you’re older.” Leo winked cheekily at his older brother before turning back to their guest. “So, little Devil man? Where do turtles go?”

The Devil in the middle of the circle glanced around the study room before donning a smile so sweet it looked like sin. “To the library.”

Instantly, the molten sigil on the floor cooled, the shadowy circle disappeared, and the Lord of Hell disappeared with a throaty chuckle and a puff of smoke.

“Awwww,” Mikey whined, flopping dramatically backwards over the side of Raph’s arms so his head dangled backwards. “I wanted to knowwwwww!”

“Oh-ho-ho,” Leo laughed in that grating, unnatural way he normally reserved for laughing at his own jokes when no one else did. “He got us good!”

Donnie set the cursed tome carefully down on one of the study tables. He closed his eyes and took a deep breath—like that did anything; stupid Dr. Feelings and his stupid anger management techniques—and then threw himself bodily at his twin. “I could have learned ANYTHING! ANYTHING, NARDO! I’m going to vivisect you! I am going to sever your motor neurons and let you WATCH while I do it!”

Raph put Mikey down, carefully flipping him upright. He looked around at the slag painted across the floor in the shape of a star, cooled but very much still cutting a line through the floorboards. “I am NOT going to be the one to tell the librarian about this.”