“Hrk!” Derpy grunted as as she heaved the last box of books onto the pile. She sighed in relief. That was the end of it. All two thousand volumes of Twilight Sparkle’s latest encyclopedia, delivered safe and sound. Mostly. One or two boxes might have gotten sticky when she’d stopped for an ice cream, but a quick rinse with the fire department’s hose had fixed that. Twilight Sparkle would just have to make sure they dried properly before using them.
And speaking of things getting wet… She checked the clock on the wall, glancing sideways at it so she could get a good look with her googly eyes. Oh no! Her break should have started ten minutes ago! Derpy bit her lip. That wasn’t going to be enough time for her to find a nice cloud and get comfortable. She didn’t need it, or anything. It wasn’t like she was an addict. Delivering the mail was just a stressful job, and it made her all cranky if she didn’t take a break now and then to cut loose. She definitely didn’t want to be cranky. Hm.
Out of the corner of her eye, she caught the ‘Erotic Magic’ shelf. Hm! Derpy looked here, she looked there, and she looked everywhere else, and there was nopony in sight. A hand snaked up beneath her shirt, giving one of the girls a quick squeeze. She shuddered. Oh, that was good. She needed more. Now.
...Maybe Twilight Sparkle wouldn’t mind if she took her break here. She was in the back of the library, after all. If she was real good, and stayed extra quiet, nopony would have to know.
She grabbed a book at random off the shelf. It was a big, black tome, with fancy gold embossments. She blew the dust off and gave it a rub with her arm to see if she could check the title.
“Heh, heh, heh…”
“Huh?” Derpy stopped. She could have sworn for a second that someone had been laughing, but she’d checked earlier and nopony was around. Odd, but oh well. The book didn’t have a title anyway. She hefted it up on a desk and got herself a nice, comfortable chair for reading it, spreading her wings across the cushiony back. She wasn’t a unicorn, and couldn’t cast any spells out of an ‘Erotic Magic’ textbook, but it would make great fantasizing material. She’d delivered Twilight Sparkle enough books like these to know they had pictures. Very detailed, very kinky pictures.
She slipped one hand down into her dampened panties and used the other to open the book up. Her breathing quickened as she pet herself, working into her rhythm as she imagined the spells the book would contain. Spells to give a mare a cock longer and fatter than any stallion’s. Spells to make her lactate like a big, milky cow. Spells to… Hold on. Her googly eyes roamed over the page, sliding right off all the gobbledygook text and ugly symbols as they searched for pictures. She flipped to another page, but again there were no pictures of big-dicked mares or anything else. And a book without any of those might as well have been blanked for all she cared!
“Ahaha!” A deep, booming laugh rose up from the book. The ink on its pages glowed a fluorescent purple. “You saw it! You saw it! You must have seen the command spell! That’s it!”
“Wuh?” Quick as a flash, she pulled her hand out of her panties, wiping away the thin line of her juices that had followed along with it. “I didn’t do nothing, I swear!”
“But you did!” the book cackled, rising up off the desk. “By opening me and reading the command spell, you fell into my cleverly placed trap. Now, once my spirit takes command of you, you’ll be trapped in the book, and I’ll be in your body. And believe me, I’m going to have so much fun with it.” It flipped open to a yellowy blank page, the name Derpy Hooves inscribed at the top. “This book is enchanted, you know. Everything written on this page will change your silly, limited body accordingly, to make it more suitable to my tastes. Once you’re trapped in here, I’m going to write such wonderful things, and you… Well, you’ll just have to wait and see, won’t you? We’ll have such a good time together, you and I — me especially, now that your body belongs to me!”
Derpy gasped. She could hardly believe this was happening. All she’d wanted was a quick break to sit down and de-stress, and now her body belonged to this musty old book?
“Say your prayers!” the book cackled, glowing brighter than ever. “Because now I own you!”
She shut her eyes. If this was the end, she didn’t want to have to see it…
…
…
“Wait.” The book glowed ever so slightly less bright. “You did read the command spell, didn’t you?”
“Um...” Derpy cracked a single eye open. She shrugged. “Maybe? I don’t read books like these much for the words. I’m a pegasus, so I can’t cast any spells or anything anyway. I was just looking for some pictures.”
“Oh no…” The book thumped straight down on the table. The book equivalent of its jaw dropping, if Derpy had to guess. “No, no, no, no… This can’t be happening. Who would even open a book as ancient and mysterious as this one without wanting to read it?”
“Me, I guess!” Derpy grinned. She could breathe easier now that she knew the book couldn’t take her body. As long as she didn’t read the command spell, or whatever it was called, she’d be safe from it and all its weird magic powers. She just had to close it up and put it back on the shelf, and not ever have to worry about it again.
Or did she? A thought struck her brain like a bolt of lightning. “What was that you said about that blank page, Mister Book?”
“Nothing!” the book snapped itself shut, quivering as if in fear. “I said nothing!”
It would take a bit more than that to fool her. Only a bit. “Sure, Mister Book,” she giggled. “Whatever you say!” She put a playful little shake in her hips as she walked over to her mailbag, reaching down to fish for a pen in the sidepocket. Normally, company pens were only used for signing delivery forms, but nobody’d ever said she couldn’t use it to write other, more interesting things. And she did still have time left in her break.
“W-what are you doing with that?” the book asked as she cracked it open.
“Nooothing!” She flipped absently to the blank page with her name on it and spread the page out. One click of the pen and she was off to the races, scribbling down every sexy idea that came to mind. Every fantasy she’d ever gotten off to. Some straight from other erotic magic textbooks, and a few from some unbelievably hot dreams. Slowly, she slipped a hand back down her panties. She was getting hot and bothered just thinking about it, to say nothing of how good it’d feel if the book had been telling the truth.
“No!” it protested. “No, stop! This isn’t what I wanted! Please! Your handwriting’s terrible!”
“You said you had a lot of ideas for what you wanted to do with my body,” she said, once she’d filled the page all the way down to the bottom. She snapped the book shut and reclined back into her chair. “How do you like all those?”
“You fool!” the book sputtered. “You have no idea how powerful the enchantments in this book are! You’ll, you’ll doom us all!”
But if it had anything more to say, it was interrupted by a beam of bright white light shooting out from its covers and straight into the Derpy’s chest. “Mmm…” Derpy closed her eyes and sank into her chair, luxuriating in the magic’s warmth. Her breathing slowed, long and deep, and with every inhale and exhale her body changed.
Breathe in. Breathe out. Every breath in sent her breasts rising a little higher, and they refused to fall back down. Two little dark spots formed at their peaks as the first drops of milk began to flow. Slowly, her head inched higher in the air, her generous hips expanding outward until they met the arms of her chair — and started pressing. A fat, ebony-black cock pushed itself up past the waistband of her panties, and she giggled as the material of her skirt tickled the rising beast. One of her hands wrapped its fingers around the growing shaft, milking it with long decadent strokes. The other busied itself cupping and fondling the orange-like balls that had sprouted up under its base, only barely contained by her increasingly tight panties. She could already feel them humming and churning with fresh cum, and only working harder as she breathed in again and they pushed outward.
“Miss Hooves,” the book pleaded quietly, even as the magic pouring from it redoubled in intensity. “You’ve had your fun now, but this is only the beginning of what you wrote. If you don’t stop now…”
Her bra was the first to pop off, unable to handle her ever-swelling mounds. The panties came next, giving her new ten (eleven… twelve…) inch dick some much-needed breathing room. Her chair creaked and buckled beneath her growing weight, but Derpy was too lost in the moment to care. Her eyes glassed over as rivulets of slick pre ran down her shaft, lubricating her strokes. A second later, the chair crashed to the floor, and her doughlike tush was granted free reign to rise over the wreckage. Achingly hard nipples pressed against the fabric of her shirt, so tight and milk-soaked now that it might as well have not existed. And soon enough, it would stop existing properly. Little rips began to form around her chest, allowing masses of grey-furred titflesh to spill through.
Not anytime soon. Derpy gasped as she outgrew her shirt altogether and the material exploded right off her. She whimpered in need as the last remnants of her shirt fluttered to the floor. It had felt so beautifully delicious to outgrow the last thing holding her expansion back, but with her shirt gone, her tits, almost painfully full of fresh cream, were feeling chronically understimulated. Her hands were unwilling to leave her new stallionhood, positively drooling now with pre. And she wasn’t a unicorn, so she couldn’t do it with magic. What was a poor growing pegasus to do?
Well, she didn’t need to do anything. She’d already written it. The book’s magic hummed as a new pair of arms sprouted out from her torso, attending immediately to her desperately needy tits. One hand pushed a grey boulder upward, where a second head suckled eagerly at the fat pebblelike nipple. Her other head sighed in pleasure, savoring the rich, filling cream as it ran down her throat. Jets of milk shot out from the other tit in time with her suckling, flooding the library floor.
“Miss Hooves…” the book began once more, but by now she was tired of hearing about it. She spared a hand to pinch the book carefully between her fingertips, then tossed it down her tunnel-like gullet as if it were a piece of candy.
“Oooooh, fuck…” Derpy hiccuped. Her body pulsed outward, expansion accelerating like never before, heads pushing up through the ceiling. The book was no longer feeding her magic on a slow drip. Now that it was digesting safely inside her stomach, she was getting all the raw, unbridled magic the book had to offer, and it felt so fucking good! Another pulse of growth hit her and she came. Hard. She felt her pony-sized balls contract inward as spurt upon spurt of pegasus seed splattered over the library. She could no longer see what was happening as her eyes went up through the second floor, but between her nigh-endless orgasm and the rivers of breastmilk pouring out from her, she could feel the first floor getting pretty sticky.
“Derpy!” A pony’s shook her briefly out of her orgasmic stupor. It was Twilight Sparkle, who had been so busy reading up in her room that she’d never noticed Derpy growing downstairs. “Is that you?”
“Mm, hey, Twilight!” one of her heads said cheerily. Her other head, finally released her tit to follow up. “I found a book!”
“What?” Twilight’s eyes widened. “What book? How did you —“
She didn’t manage the end of the sentence, as another spurt of Derpy’s cum broke up through the ceiling and soaked the room from ceiling to floor.
“Oops!” Derpy giggled, bringing a pair of hands up to wipe off her face, while the lower pair paid constant attention to her more sensitive bits. “Sorry, Twilight!” the other head laughed.
The floor creaked ominously, the wood swelling as Derpy’s growth continued and her tits looked ready to follow her heads upward. Streams of fresh milk welled up from the cracks, forcing Twilight onto her jizz-soaked bed to avoid getting any messier. Down on the floor below, Derpy could feel her balls swelling and churning, pausing her orgasm only to ready an even bigger batch of cum. She could feel it, all the way down in her tummy. The book was preparing another burst of magic, eager to move on to the next stage of her growth. It was going to be a big one.
“You might want to…” one head began.
“...Make a run for it.”
-
To the ponies of Ponyville, it had seemed like a normal morning. Had. Just until Princess Twilight, thoroughly basted in some thick, white fluid, had shot out of her own bedroom window screaming in panic. What exactly had happened to Twilight Sparkle was anypony’s guess. The only clue came from the library itself, where the thick white stuff Twilight had been covered in leaked in growing streams from the windows. But it hardly mattered what they thought Twilight was running from. From the spiderwebbing cracks in the library’s walls, and the deep, thundering moans that resounded in stereo, they’d be running from it too in very short order.
