Image imported from derpibooru 
Original Description:
 
Original Picture done by Fetish Sketches. I just added more tendrils >:3
 
Done with permission!
 
Short Story done by a friend:
 
Late Night at the Library
 
Twilight hadn’t bothered getting her slippers. She was only going to tiptoe down the stairs to get a few books for some late night reading. Minutes past midnight, Spike was still fast asleep upstairs.  
Still in her pajamas, and set with small firefly lantern, Twi crept to the back of the library, looking for any titles that caught her sleepy eyes. The light, springtime rain was starting to roll in just outside, but the center of Golden Oak stayed warm. As Twilight made it to the back ends of the library, she started to notice some of her more advanced studies. Sent in from Celestia’s own collection, they were collections of all sorts of bizarre studies and ancient magics. Many of them contained spells even beyond twi’s abilities.  
Nevertheless though, she finally settled on a book to read for the night, setting down her lantern and pulling aside a small set of steps to reach it.
 
 
As she reached though, getting right on her tiptoes, she hardly even noticed knocking over one of the old, grey tomes, sending it behind the shelf.  
“oops, better be more careful with these” twi silently chided herself, still reaching for the book at the top of the shelf. Just beyond her sight though, the book had fallen open, revealing a fold of pages, seemingly oozing flows of strange ink. These books needed to be handled with care, and twi would soon learn why. Just out of the glow of the lantern, the ink started to flow into the shape of long strands, inching closer to the base of the steps.  
Twi still absent mindedly ran her fingers across the spines of the books, casually deciding which one to get. The growing tentacles of magical ink noticed the motion and the warmth, and started to close in. They crawled up the steps, approaching the studious and completely unsuspecting unicorn. Dark black ooze surround the stretch purple soles bathed in the yellow glow of the fireflies. The curse was cautious, not striking until it surrounded the soles on all sides, all hovering just above the slightly dusty bare feet. As they waited, smaller tendrils started to form, melting into half a dozen shapes: small little claws, wiry Graspers, and tight little clamps for the curled digits.
 
 
Just as twi wrapped her fingers around a book, her breath caught in her throat. A flowing, cold feeling struck her bare soles. The sensation was quickly followed by something else though. The ink had laid siege to her feet. The tendrils swarmed her, coiling around her arches, around her insteps. It squeezed between her toes to form little rings and around her heels to start crawling up her pajama pants. The tendrils wiggled and pressed into her bare feet, webbing across them lIke and tightly holding on. Instantly, twi was already feeling her stomach flutter and her chest rise with bubbling laughter. She barely even got to look dowith before her feet were almost covered. The tendrils were moving past her ankles, grabbing onto her as all the shapes started to dance and swirl.  
“EEK!! Ehehehe!!! No no no!!”
 
 
Twi tried to shimmy the ink off but it was thoroughly on her now, and thicker flows were fast approaching. She had to get out of here, but as the wires of ink coiled around her ankles, she felt more and more stuck. The magic from the book was beyond her ability, and if she didn’t get help soon, she was gonna be in for a long long night…