"In the wake of the Nightmare's most pathetic assault on Ponyville yet, Applejack is thrown into an existential crisis, despite her not knowing what the word "existential" means. So when a stranger named Stranger arrives in town, teaching a new way of coupling talent to power using complex machinery, she is quickly suckered in, along with everypony else. Now, it falls to the Most Dependable of Ponies to bring the resulting ruckus down to earth, but can even Applejack's legendary pragmatism stand up to the brain-fizzing horror that is… CONTRAPTIONOLOGY?"A Crack Fic the way Crack Fics should be written, Contraptionology! is a finished fanfiction by Skywriter, who also wrote Princess Celestia Hates Tea. It can be found here, and it's prequel one-shot story Infernal Machines can be found here.
Book Burning: A clear sign that Twilight is losing it, when she has the entire content of the library burnt by Spike - to make more room, and because she thinks they disagree with her findings. Seeing as she rebuilds the library in the end and doesn't seem nearly as heartbroken about it as you'd expect a bibliophile to be, she either got replacements, or Spike teleported everything to Celestia instead.
From Bad to Worse: Things were already pretty bad with most of Ponyville and the Mane Six suffering from SRMD, then along comes chapter sixteen in which Rainbow Dash is apparently vaporized and a badly injured Applejack is about to be killed by Robo-Trixie.
Lampshade Hanging: in the Epilogue, Applejack metions this is the third time this year they've had to rebuild Ponyville and adds that we're "kind of getting a rhythm for it."
Large Ham: The Nightmare, which makes ponies rave about making mundane things last FOREVER!, and von Danger, who actually hires Derpy to follow him around with a thundercloud to give his words "the emphasis they require."
Noodle Incident: According to Celestia, Berry Punch annihilated all of existence, then remade it again a millisecond later, in response to a massive bender from drinking all of the remaining lemon punch.
Science-Related Memetic Disorder: Pervasive throughout the entire story. In-story, the field of contraptionology can actively induce this although not nearly as fast as it happens in Ponyville, where Discord is speeding up the process. Lampshaded early when Applejack puts together a Jacob's Ladder for her lab just for the heck of it.
Applejack: [...] I ain't all book-learned like you, or apparently, Pinkie Pie, is.
Twilight:drops everything she was telekinetically holding Oh, that Pinkie Pie! Has she been regaling you with some of her random and totally untrue stories again?
Applejack: Uh, maybe?
Twilight: Hoo hoo! What a laugh! Boy, she was telling me a real whopper earlier today, I don't know, maybe it was the same one she told you! It was just some crazy and, let me stress, totally non-true, story about how she's secretly a doctor of advanced contraptionology with a degree from the Maresachusetts Institute of Technology and how while she was in college she made a mechanical lizard that makes 'squonk' noises and breathes fire when it eats hot food and it came looking for her and that's what started the forest fire last night and so now we have to return it to her thesis advisor in Maresachusetts and that's why we're going on a road trip! It was funny because of how patently not-true it was!
Sound From Kitchen- SQUONK!
Talking Is a Free Action: Rarity stops running from the mutant bees long enough to complement Nightmare Delicious on her outfit.
Unreliable Narrator: Applejack spends most of the story under effects of first sleep deprivation, then three different forms of mind-altering magic. Generally it's made clear to the reader what's going on but the significance often flies over her head as she narrates.
Villain Decay: The Nightmare, once a genocidal threat to Equestria, is now the terrifying filly of darkness: NIGHTMARE SCOOT! She recovers most of her dignity in the story.