“Well?” asked Starlight Glimmer, lying on Trixie’s bed.
“We’ve been assigned a quest.” said Twilight Sparkle, shrugging her bag off her shoulder and closing the door.
A spit came from the bathroom as Trixie Lulamoon finished brushing her teeth. Only her head appeared from the doorframe, as she was not yet decent. “A quest? Really?”
“What kind of quest?” asked Starlight, sitting up.
Twilight relayed to them what the princess had told her, then the three girls excitedly got to work making preparations.
The princess provided for them protective cloaks of equinox-moonsilk, the shifting threads capable of warding against both heat and cold.
Their Grimoires on their belts, each packed a satchel with a fair amount of materials, as they would be venturing beyond the protection of the Academy Enchantment.
They left the grounds at high noon and followed the trail as it wound about the base of the Canterlot Cliffs toward the entrance to the profaned Dawn-Dusk Cavern, which ran deep beneath the capitol.
The entrance was unmarked save for an inconspicuous runic ward carved into the inner wall which Twilight deactivated with ease. She led the way into the cavern with a low-upkeep illumination spell, the others close behind.
The grade was steep and the path was winding. They had been walking for what felt like half an hour when at last they came upon the cavern proper.
The great chamber was such that the ceiling remained unfathomable despite Twilight’s spell, which she broke as they approached a glow emanating from the middle of the room.
The light came from a small amber, resting in a vessel of carved orichalcum suspended by a helix of roots rising from the floor.
The trio gathered around, their faces lit from below.
“This is it.” said Twilight softly. “The Sap of Harmony.”
“Has this been here the whole time?” asked Starlight without looking away.
“It only appears once every eight years, formed from a wound in the roots above us, which are said to belong to one of the Trees of Harmony.”
“Wait, Trees?” asked Trixie, looking up at Twilight just in time to notice something moving behind her.
It was a mimicry of shadow, not banished by the light. Before Trixie could say anything the glossy tendril slipped beneath the collar of Twilight’s shirt, sliding between her shoulder blades, tracing her spine down to her lower back.
Twilight screamed, fumbling behind her, trying to dislodge whatever it was. “C-Cold! It’s cold!”
“Twilight?” asked Starlight before a second tendril slipped underneath her cloak. “Hey, what-?” The tendril plunged into the back of her skirt, slotting neatly into the groove between her butt-cheeks as it slithered under her panties, the frigid tip touching the bottom of her pussy and eliciting a startled yelp.
A third tendril bypassed Trixie’s cloak and ran its way up her shirt, over her stomach, then coiled around her left breast, pressing on her nipple with its frosty tip.
“Gah! What the heck?”
Ever rash and quick to act, Trixie shrugged off her shirt and cloak to the initial surprise of the others. However, they all saw clearly the dark thing writhing about against the light-blue backdrop of Trixie’s coat, squeezing her boob and flicking her nipple like a long, black tongue.
Disgusted, Trixie grabbed the thing with her bare hand, ripping it from her tit. As it writhed in her grip she cast a fire charm, the flame searing the tendril and causing it to withdraw violently into the darkness above.
“Try fire!” Trixie shouted.
Twilight begrudgingly lifted her shirt, squealing as the thing thrashed about against her back.
When she finally shed the garment the tendril was still trapped within.
Twilight cast the same fire charm, setting her shirt ablaze. As the tendril flailed about, the moonsilk cloak slipped off, untarnished.
“Guys, help!” cried Starlight as she was hoisted into the air, the freezing tendril scooping her up between the legs, digging harshly into her slit.
Trixie and Twilight turned to face their friend, who was clenching her teeth and crossing her legs. Trixie scorched the tendril and dropped Starlight while Twilight cast a feather-fall spell to soften her landing.
“Get it out get it out get it out!” yelled Starlight, scrambling to her hooves. She caught hold of the severed tendril and yanked it out, shivering as it slid across her pussy and out the back of her underwear. It felt like wet seaweed, and as soon as it was removed she hurtled it into the furthest reaches of the room, sending fire after it.
Then the three girls stood with their backs to the amber as more tendrils came down from above, drooping like snakes from a jungle canopy.
“We need to cast a fractionary spell!” said Twilight
“But we’ve used up too much material!” Trixie replied.
Twilight recovered her moonsilk cloak and tossed it over the amber. “We can use the Sap! If I understand correctly, it should act like a philosopher’s stone.”
“Is that dangerous?” asked Starlight.
“The moonsilk should allow us to draw from it without touching it directly.”
That wasn’t exactly an answer, but nevertheless Starlight placed her hand on the amber along with the others, all of them readying their grimoires.
“Now!” shouted Twilight.
A sudden conflagration set the ceiling aflame with a myriad of colors, severing the tendrils which jerked and writhed as they burned.
There was a mind-raking shriek, more felt than heard, and the goo began to fall in burning globs.
“Run!” shouted Trixie and Twilight in unison.
Twilight dropped the amber in her bag and recovered her cloak. Trixie fetched her own and the three of them bolted through the forest of flame, using their moonsilk mantles to ward off the rain of fire.
They barreled down the tunnel, never slowing or looking back. They could feel the heat on their backs, a stygian fury clawing at their minds.
Twilight reactivated the runic seal as they stumbled into the evening light, trapping the horror within.
Author's Note
Took way to long to shorten this one. Hopefully it is an enjoyable read. 
