Hypnagogic
It was the witching hour: three in the morning. The phrase came from ancient superstition, the sort of thing that Twilight Sparkle was studying.
Twilight was an oddity; she enjoyed studying at such unholy hours. Not because she needed to, though. Well, she had a goal to meet before she would finish this research bender. But that was her choice: the Princesses didn't command it, and there was no disaster to stave off.
She simmered in books for fun. But everypony knew that already.
Alas, the scholar was not a metaphysical entity; consigned to pony flesh, her mind demanded maintenance to hold back the hordes of entropy. Food, water, friendship--and sleep.
Sleep is for the weak. The flesh is weak--the spirit is willing, oh so willing.
Twilight yawned. Sleep was a perverse injustice inflicted upon her; as a filly, she despised bedtime with an ire typically reserved for bitter vegetables. Even as an adult, she could work up little more than an uneasy truce with sleep. There had been cases, she heard, of ponies that did not need much sleep; Twilight had been thoroughly envious of them, and begged the doctors to try and make her one of them, to no avail.
A particularly dense paragraph taunted Twilight's bleary eyes. She redoubled her intellect and parsed the meaningless words. Earth pony witchcraft...the seventh century...cultic behavior...unspeakable rituals--from the dense lexical tangle of archaisms the scholar extracted understanding, as the great wizards of old transformed stone to flesh and drained the blood.
The words began to twinkle upon the dimly-lit scroll. A hypnotic shine came over the paper as Twilight saw its contents reenacting themselves before her eyes. Ah! There it was, the concept for which Twilight had been striving! The cultists...the pyre...the uninitiated masses...the pyre set upon itself as the souls danced; such an elegant procession, this was precisely the concept she needed; though the witch-cults were brutal, perhaps their wisdom and their knowledge of wizardry was grand indeed--
Twilight came to. It was but a meaningless vision from the precipice of sleep. Exactly what it was, she'd long forgotten.
Focus. She continued drilling for knowledge. The slate of words before her remained thick, and the unicorn was already spending much effort holding her eyes open.
One word stumped her: bespoken. "For bespoken lures of boundless power," the text said, "did enthrall low and high alike." The word, she was starting to realize, meant nothing to her. She had once assumed it was just a fancy form of "spoken." But she looked it up, and it meant something else. Besides, the rites of the witching hour were always silent.
She knew the meaning somewhere beneath the sleepless addled haze, perhaps. But such a rare word was filed too deep in her mind, and the lights were quenched in the obscure sections of her mental archives.
Though at least she knew that "bespoken" wasn't "spoken." Rainbow Dash's didn't. As somepony new to writing, Rainbow Dash came to know of many words--most of which she misused in an attempt to sound "super smart."
The end result was, unfortunately, more goofy than erudite. Dash's narrative voice sounded like a pony who tried too hard to seem intelligent in order to cover up their ineptitude--which may have been exactly the case, not that Twi could tell say such a thing to her friend's face. Rainbow Dash's habit of not checking her work didn't help things, either.
So Twilight found herself trying not to laugh while reading a book containing lines like "'I'm going defeat you' the monster said somatically." and "Before Prisim stood a veracious deamon. 'Roar,' he roared veraciously." It kind of took the fun out of reading bad books if you couldn't laugh at them.
Twilight had been staring at "bespoken" for some time now. How long? Long. Very long. Too long. Time to move on.
Rather than risk another hypnagogic trance by puzzling out the meaning of funny words, Twilight decided to try a different activity. The text described a magical effect; did it happen? Was it even possible? She could make a rough estimate of the probability, at least.
Compute the root field magnitude, factoring in the Frog effect for the stronger background magic back then. Guesstimate the field strengths of the reagents; she had memorized most of them anyway. Construct a recursive-field system similar to the scene described. Perform eta-transforms until the system approached gimel-equivalence. Carry the two. Apply the Clover identities and see if the physical effects of the ritual were plausible.
Negative seventeen percent probability. Negative.
This was getting ridiculous. Sleepiness was getting in the way of her research. There was no choice; she'd cast a wakefulness spell on herself.
Well, she could just go to bed, but what was the fun in that? She couldn't stand coffee or tea, either, so there was only one option. Wakefulness spell it was.
Sure, Twilight Sparkle enjoyed magical problems more than anypony had any right to, but that had nothing to do with her decision.
Casting such an enchantment was simple. Casting it on herself was a very different matter. As the spell needed to propagate a minimum distance to work, it had to be channeled through a metaphysical loop. Said loop was fragile, yet, if it broke, the spell system would collapse and perform, well, "undefined behavior" was the technical phrase. Twilight never bothered putting it into laypony's terms; it would have been ugly.
The prospect of explosive complexity gave Twilight a frightful shot of adrenaline; merely trying to cast it without causing a horrible accident made her more alert. First would come the loop. Building it was much like calculating a recursive field system, but easier: get a feel for the background magic field, and layer more magic on top.
Creating the loop was effortless for such an experienced magician as Twilight. But it required active effort to maintain. Easy enough--when not casting a second spell.
Now she had to shoot the wakefulness spell into one end of the loop, and hold the construct together until she felt the effects. Simple, right?
Nervously, Twilight cast the spell. The spell wave proceeded normally, the pulsing purple light Twilight knew like the back of her hoof. It reached the loop--and slowed. Twilight finished her end of the cast, yet the spell looped, twisting and turning like a scared worm through syrup. The tail end of the spell's beam slid into the loop, and the head emerged. It curved at the wrong angle and moved much too slowly. Only then did Twilight realize her mistake.
The loop shattered before the main spell even began to reach her.
There was no explosion; Twilight was lucky. Instead, there was a single tone, loud, high-pitched, yet not abrasive. Nonetheless, it roused all of Ponyville and left Twilight's ears ringing.
It was embarrassing, of course. Everypony came to see what was the matter. One by one, she reassured them, and apologized to the more annoyed neighbors. This would be tiring had Twilight been fully alert. Combined with sleepiness, it was all but unbearable.
Finally, the drip of concerned ponies ceased. Completely spent with no other options left to renew herself, Twilight collapsed snoring on the floor.