Sera dragged Marzel all the way home after taking her dog out for a walk in the park last night. Of course Marzel had to mount a human bitch and make out with her dog, and put on a dreadfully boring show. "Get up," she says the next morning, kicking the lazy bitch in the ribs to wake her up. "It's time for you to help out in my stables."

Marzel had fallen asleep on a sidewalk in Sera's garden, and rises with a smile from the familiar scent of her master, and the texture of her foot. "Mmh?~ M-whuh??" Marzel wasn't much of a morning person, and was slow to get up, but at least she was in a good mood. "Stables?" Sera sternly replies, "Yes, my stables, full of all manner of magical beasts. Your help is needed, slave." Marzel rises to all fours as Sera yanks on her leash, happily replying, "Oh yay, stables!" She pads along, following Sera's brisk strides. She plans to help out, alright. Even though she's sterile and infertile, she'll pretend to be a good breeder every step of the way, just so she gets some primitive sex.

Sera leads Marzel into the stables, where the usual ordinary critters like horses and dogs can be seen near the entrance. "Well, my little bitch, what kind of monster would you like to mate with?" "Tentacles!!" Marzel replies without hesitation. "Very well," Sera says with a sly smile, leading Marzel down the walkway on the left. At the edge of the stables is a twenty-foot deep pit, filled with writhing black tentacles. It's too dark to see them at the bottom, however. Marzel leans forward, listening attentively, her cunt already dribbling in anticipation. Sera unhooks the leash from Marzel's collar, gliding the top of her foot up Marzel's thighs and pressing it gently against her exposed cunt. "Dirty fuckpig," Sera spits at her slave before she brings that foot back and delivers a swift kick to Marzel's slutty fuckhole. The force of the kick makes Marzel do a flip into the pit below.

Marzel cries aloud as she tumbles into the pit. Her legs sink into the squirming mass first. The tentacle beast roars upon impact and violently seizes her arms, wrapping tendrils around the rest of her body. "Aaah! T-thank you, mistress!" Marzel calls up at the darkness above her, but surely Sera can't hear her over the low groan of the tentacle beast and sounds of slimy tendrils squirming against each other. The pit is rather lively now that new breeding stock has been added. In seconds, Marzel looks like a zebra, she's covered in so many tentacles eager to prod her flesh and feel where her entrances are.

The tentacles get to work straight away on rubbing four thick phallic-shaped inseminators against her pussy and asshole, spreading their warm tentacle slime all over. She gasps in pleasure and anticipation, left wondering how many the beast plans on cramming into her. Each one is already as thick as her wrist, the ideal girth for her, but she half-expects this tentacle beast to force them all in. Marzel decides to get playful and try squirming against the tentacles, pretending to be a blushing and reluctant victim, but the tentacles violently restrain her and the hivemind unleashes another subsonic groan. These tentacles were cruel, and demonic in nature. A few extraneous tentacles not yet touching Marzel, but ones hovering close by, strike against her and leave dollops of smelly tentacle slime on her, not unlike human precum, but with an intensely savoury musk to it. Clearly they're trying to beat the fight out of her, and make her submit. To hasten that process, the tentacles waiting at Marzel's holes suddenly plunge in, one at a time.

"Aaaagh! Yes, yes, gimme your cocks!" Marzel cries in whorish pleasure. The tentacle monster reacts instinctively to acoustic pressure on its tendrils and silences its victim before aid can arrive, sending another inseminator tentacle to Marzel's mouth, fucking her throat deep enough to form a visible bulge. The force is intense enough to push Marzel deeper onto the tentacle in her pussy, which bashes its way through her cervix and visibly coils inside her uterus, stretching it out to prepare for what will come later. A second tentacle joins the silencing effort near Marzel's lips, taking turns with perfect alternation to ensure she's constantly deepthroating at least one of them. The tentacles entering her holes all have subtle bumps on them, which stroke Marzel's growing clit-cock from below on each and every thrust into her. "Mmmmph! Mmmmm!" Marzel squeals in pleasure as the tentacles rape her. She can tell this is a baleful and ancient species that has been an enemy of civilization since time immemorial, just from how violent its thrusts are.

After some time, the tentacles in Marzel's holes unleash their cum. All three of them withdraw, and are replaced by identical ones, in a mad pursuit to impregnate Marzel. Though they noisily push the last batch of tentacle cum deeper into Marzel, they don't continue for very long. The hivemind seems to have realized that Marzel isn't capable of ovulating, and seeks to do something about it. The tentacle in her pussy grows tiny spines and begins spinning, shredding the insides of Marzel's womb into a bloody pulp. The blood rushing to Marzel's loins to begin healing her means she has a lot more blood flowing into her clit, causing it to throb and reach a monstrous size of six inches of female flesh. Marzel instinctively reaches for a spell to dull the pain and flood her body with endorphins, thanking her mistress for increasing her tolerance to pain since entering into Sera's service. This tentacle species was indeed evolved over millennia to torment and demoralize metahumanity, and they were about to prove it in the utmost.

Before Marzel can effect any more magical changes, the tentacles disrupt her spellcasting by flooding her with an altogether different substance, a thick black goop that only the most vile creatures can produce. The tar-like substance floods her cunt and her ass, preparing them for the next stage of her breeding cycle. The tentacles reconstruct Marzel's womb into an inhospitable wasteland for anything but demonic and invertebrate life. Her ovaries regenerate, organs not seen in her body since she was a teenager, and fill to the brim with fresh eggs, as if to catch up on decades of missed production. Marzel squirms in protest, not wanting her body to betray her and allow anything to get in the way of her favourite activity of womb-fucking. Thankfully, the tentacles grant her her deepest wish and send two smaller tentacles up her cunt alongside the shredder. Each one plunges up her fallopian tubes, and begin extracting every single egg for some sinister, unknown purpose. Marzel's womb is now a blank slate that can react to any sperm or eggs implanted into her, so long as they came from sufficiently evil creatures...and on that note...

The tentacles withdraw from Marzel's holes, in order to make room for different, more specialized limbs. Marzel coughs up the remaining half of tentacle cum she can't swallow fast enough, her face becoming a mask of tears and cummy spit as her head leans back. Now that her tits aren't wobbling around like crazy, a special pair of prickly tentacles approach and stab her nipples, making them swell immediately and begin to dribble milk from the fleshcrafter's familiar pleasure of growth. Her clit spontaneously evolves into a cock and surges ahead to nine inches tall, cutting at the air like a fleshy knife. The tentacles still flowing over her body and restraining her brush past it incidentally, not avoiding it, but not paying attention to it either. Perhaps the pit dweller already sensed she was a converted futanari...or was unworthy of being turned into one.

The process of enlarging her nipples, however, served a darker purpose. Once her nipples are big enough for insertion, two narrow tendrils stab their way into her tits and begin flooding them too with the same blackened corruption, preparing Marzel's holes for what is to come.

While Marzel is caught between breaths and trying not to choke on tentacle cum, she is suddenly forced to remember that she's been turned into a full succubus at this point, whether by Sera's contract or by the tentacle nest's violent remaking of her innards, by the new tentacle entering into her throat. This one is a little more transparent, with a texture like concentric rings. Marzel can see spherical eggs headed down it, and also sees a swarm of similar tentacles gathering around her defenseless body. The prickly tentacles at her nipples continue to toy with them, altering them to the point where they can be stretched open, revealing a mess of milk and sludge within. Soon Marzel is taking ovipositor-tentacles in her mouth, her ass, her pussy, and even one in each nipple. A procession of eggs marches constantly into every one of her holes. Marzel cums as soon as the third egg rolls into her womb and rests heavily against the others, her cock painfully hard as it shoots geysers of cum all over her skin and the tentacles covering it. She can feel it growing past a foot long and changing into its demonic shape due to all the demonic essence the tentacles are pouring into her, in order to prepare her to be a proper breeding vessel. She can feel all the spherical shapes bulging out her skin in irregular places, even making grotesque shapes in her heaving breasts.

After several minutes of laborious oviposition, the tentacles withdraw at last, and let Marzel rise to the surface of the nest. Her throat, stomach, and vestigial digestive tract are filled end-to-end with an unbroken chain of eggs. Her womb is stuffed completely full, bulged out to well beyond a third-trimester pregnancy. The only space in her body not filled with tentacle-bearing eggs is her cock, which remained hard and unwavering while continuing to weep cum. When the ovipositors are finished, the inseminators return and rub themselves all over Marzel's now much softer body, until they're ready to cum and pour their cum into Marzel's holes once again, this time to fill in every gap between the eggs with fresh nourishment.

Comatose with mind-shattering tentacle pleasure, Marzel puts up no resistance as the tentacles lift her up to a low section of the pit's walls, which is completely covered by their wriggling mass. The wall of slippery flesh parts, absorbing Marzel's legs up to the thighs, and pulling her wrists above her head and through the mass as well. Finally, one last inseminator shoves its way past her cunt-lips, ensuring no eggs would fall out of the most important of Marzel's warm holes. She resembles a torch, the way she protrudes from the wall like this, except no one would ever see her in that darkness at the bottom of the pit, against a backdrop of solid black tentacles.

* * *

Marzel would remain in that pit for a few days, incubating the eggs inside her while in an orgasmic state, eyes scrolled up out of sight the whole time. Her skin is plastered with a mix of tentacle cum, and her own. She'd be busy eating it if she wasn't completely stuffed, and still entangled in the inky black tentacles. She would only get to cum from her cock once that entire time. About halfway through her breeding cycle, her cock was borrowed to stick in another girl trapped in the tentacle nest, and feed a massive load of Marzel's corrupted cum to the unborn tentacle spawn in her womb. The girl was lifted and impaled from above by Marzel's sixteen inches of demon cock. The tentacles holding Marzel to the wall only have to gradually slacken their grip, using merely the weight of Marzel and all the eggs in her to slowly grind her cock into the girl's defenseless pussy. The teenager screams in pain the entire time, especially as her cervix is inevitably caved in. Not even that can bring Marzel out of her mind-broken state, constantly dreaming that her cock is dirty with baby tentacles and looking for a womb to put them in...