"What?" Nightmare Moon hissed.

Daring Do shook her head, her face flushed, a quiver in her voice. "Your guards. They'll interfere if you start losing, even if you tell them not to."

Nightmare Moon ground her teeth. The impertinence!

"They wouldn't dare," she snapped, slit pupils narrowing.

The two of them stood at opposite ends of a vast, dark courtyard, its ancient stones scoured clean of the vines and debris that had coated them before Nightmare Moon's triumphant return. Around the edges, on an elevated battlement like the seats of an arena, throngs of ponies were gathered; bat-winged guards, nobility, servants, slaves, all gazing down at them. The moon shone down from directly overhead like a beacon, casting silver light that lit the world almost as brightly as full daylight, but colder, more remote.

Compared to Nightmare Moon's own magnificent armour, shining black and silver, Daring Do wore nothing but her ragged explorer's outfit, with a set of odd, shiny gloves coating her hands. She looked very small and out of place amongst the grandeur of the castle, as she should. The foolishness of the rebel, the gall! After all the trouble she had caused her rightful ruler, to demand a duel for the fate of Equestria!

Well, letting the ignorant little fool trot out of whatever hole she was hiding in and right into her own waiting hands was more than worth indulging Daring's foal-naive fantasies that she actually had any chance of victory. A sneering smile of anticipation curled across Nightmare Moon's face.

"...fine. Fine! If you wish to be trapped here in my presence..." Nightmare Moon's long, sharp spire of a horn curved through the air. Magic bled from it, arcing outwards and forming a shimmering bubble over the courtyard that anchored in the stones walling it in from all sides. "...you shall be," she finished.

"How long will the shield hold?" Daring Do asked huskily, another tremor quivering visibly through her body.

"I have had enough of your lack of respect! It will remain unbroken for a quarter hour, regardless of what any pony does, which will be more than ample to crush you beneath my heel so thoroughly you will confess the names and locations of the others before my entire court! Now, stop wasting my time, and fight me!"

A shaky giggle escaped Daring Do, who was obviously too scared to maintain her composure. "Okay. I can - yes, I can hold on that long."

"You are sorely mistaken!" snapped Nightmare Moon. Her horn swung through the air, a glow kindling at the needle-sharp tip.

Daring Do was already gone; the explorer had shot into the air as if fired from a cannon, kicked off the misty shell of the shield overhead, and ricocheted back towards Nightmare Moon from above. A searing beam of blue-white magic sizzled past the pegasus as she banked and rolled, then another.

Nightmare Moon twisted aside as Daring Do shot past, though it was scarcely worth the effort; what did the little fool think she could achieve against the most powerful alicorn to have ever lived, with her bare hands no less? She didn't even have magic!

No; her hands weren't bare, were they. Those gloves. Nightmare Moon didn't recognise them, nor the slick, shiny material they were made of. Could they be some kind of weapon? Daring Do banked and twisted, bouncing off the courtyard wall and coming straight back for her, glistening hands outstretched. Nightmare Moon snapped out her wings, kicking off the paving stones, and surged backwards out of reach.

Daring Do landed, her cheeks flushed red, breathing in small, jerky gasps. "Not - mmmh! - not bad, Nightmare! Going to keep running away from me until the time's up?"

Nightmare Moon hissed at her through her fangs. Above the two of them, the head of the royal guard led the court in cheering and shouting for their absolute ruler, helmet removed to bare her rainbow mane. "I have crushed everypony who dared stand before me. I certainly don't fear you."

"Everypony? Because you only managed Celestia on the second try-"

Fury exploded behind Nightmare Moon's eyes, and a searing line of blue-white energy swept across the courtyard, slashing across Daring Do's body. The explorer shrieked, tumbling backwards to lie still, her clothes torn into rags that fluttered down in her wake like tattered snowflakes.

Nightmare Moon snorted. "Let all see the futility of resisting my rule!" she thundered, revelling in the cheers, before striding across the flagstones to where Daring Do lay. To where... wait.

Daring Do lay on her back, small, whimpering gasps escaping her, but those sounds weren't sounds of pain. That was - that was lust! And where her clothes had been shredded by the shock of the magical impact, she was coated everywhere beneath, neck to toes, in the same slickly shiny black substance. Nightmare Moon slowed, her last few steps almost hesitant, as Daring Do helplessly humped the air.

"What - what is this?" she demanded.

"It's a present, nnngh, a p-present for you!" gasped Daring Do, rolling over and thrusting out a hand to grab at Nightmare Moon's boot.

"Get off me!" snapped Nightmare Moon, jerking backwards. She looked down at herself; Daring Do had left a handprint of the shiny, liquid material on the metal. Well. She certainly wasn't touching that.

Then, without warning, it beaded up, and flowed into the joints of her armour.

"Wh- what?" screeched Nightmare Moon, her heart hammering in shock. She bent over, grabbing at her leg, but there was a slick coolness flowing up her calf and thigh beneath the metal, and she couldn't get at it. There was a murmur of confusion from above, dampening the cheers, but all she cared about was finding a way to stop whatever it was that was happening, tearing at the fastenings of her armour.

The slickness flowed into her panties, and coated her sex. A flare of electric pleasure crackled through her, as though a dozen tongues were suddenly prying at her tender lips and sucking on her clit. She doubled over with a gasp, the sensation almost unbearably intense. What was this?

Daring Do's hand gripped her shoulder guard, and liquid darkness began to flow over the metal, crawling beneath it.

"No!" gasped Nightmare Moon, lashing out with her arm to knock the mare away from her.

Daring Do went flying, tumbling, but as she impacted the flagstones, she once again cried out in pleasure. Bracing herself on wobbly legs, the flier pushed herself fully upright, every trace of her clothes now gone. She was coated in sleek, shiny black, clinging to every inch of her body. Stiff nipples jutted out from her well-formed breasts, and the slick material coated every detail of her pussy with anatomical precision. One gloved hand rose to knead her breasts, and she breathed huskily, "How does it feel, Nightmare?"

Tendrils of slick material were crawling under her breastplate, sliding over the surface of her generous breasts, tightening and loosening, as if they were being kneaded forcefully by unseen hands. Nightmare Moon grit her teeth, fighting back the sensations, even as the unnatural material began sucking and squeezing her nipples. "I - I will destroy you for this!" she snapped, infuriated even further by the quiver she heard in her own voice.

Daring Do giggled - the little bitch actually laughed at her! - and kicked herself into the air once more. She was fast, incredibly fast, but Nightmare Moon knew she was faster, and as the taunting, infuriating pegasus sped towards her, her horn lit with a blasting spell that would smash the irritating insect once and for all.

Invisible, slick fingers pinched her clit and nipples, hard, all at the same time. Nightmare Moon jerked, a yowl escaping her mouth, and before she could react, Daring Do slammed into her. More of the black fluid flowed over her armour from every part where they touched, crawling, insinuating itself. Stumbling, Nightmare Moon jerked away, swiping her arms aimlessly to keep Daring Do away, but the other pony wasn't pursuing her.

"Too late for you," panted Daring Do, with a wobbly grin. "That's more than enough."

"Silence!" screeched Nightmare Moon, clawing at the glistening tendrils crawling over her body. The thick, viscous liquid came away in thick, stretchy ropes, webbing her fingers and coating her hands before beginning to flow up her arms again. A strange, burning smell wafted around her for a moment, before her breastplate jerked, and fell loose to the ground, the cloth holding the fastenings having burnt away. There wasn't even a trace of her bra. Her tits spilled free, entirely coated in liquid blackness, and there was a roar of noise from the ponies above the shield.

The shield! She had to break it, to get away! She concentrated, half-doubled over and trying to think past the surging, invading pleasure, as a pressure built beneath the armour over her crotch. With a sudden ringing of metal on stone, several more armour plates crashed to the ground like a brief, heavy rain as their cloth backing dissolved. A hopeless, furious moan of pleasure spilled from her lips.

"Running away means forfeiting, Nightmare!" called out Daring Do, with a breathy, giddy delight in her voice. The explorer wasn't even trying not to touch herself anymore, her shining fingers thrusting in and out of her dripping sex. Trickles of her juices beaded on her thighs. "Here, let me give you something to think about!"

Nightmare Moon tried to spit a rebuttal, but never managed to get the words out. A thick surge of the glistening material forced its way into her soaked cunt, and her knees nearly buckled as the intolerable sensation of tongues and lips and fingers caressing her clit and nipples was joined by the deeper, more powerful thrusting of a shaft that impaled her to the hilt. She was almost nude now, coated in perfect, slick darkness like a second skin, only the last shreds of her armour clinging to her body.

"What - I will, nnh, I will destroy you, what is this, what have you done?" she howled.

"You're, ohhh, oh fuck, you're repeating yourself, Nightmare!" gasped Daring, a wobbly, dizzy smile on her lips as she approached, step by step. "Ever heard the phrase, 'lesser of two evils'? Oh, fuck, that's so good, that's so good," she hissed, her fingers pistoning in and out of her. "Legend says this stuff converted a whole, mmmh, a whole slave army, had to be sealed away forever. I went looking for it. Found it. Let it take me. All for you. You're gonna be my slave, Nightmare. An army of one."

A crashing thunder of rage thudded through Nightmare Moon, so intense that her vision darkened at the edges, and she brandished her hands like claws as the last of the armour slid from her body and struck the ground. "Never!" she snarled, almost incoherently. "I am the one who rules!"

Daring Do breathed in deeply, an expression of acute concentration on her face.

Nightmare Moon shuddered, a whole body shiver that rocked her on her feet. Something was happening, something hot and heavy and strange. Her eyes snapped downwards, and to her shock, she saw her breasts were swelling outwards, her ass growing wider, her thighs thickening. Her cunt was outlined perfectly by the glistening material, even though she could still feel the phantom shaft fucking her over and over, ripples teasing and pinching her clit. She was so sensitive now that she could barely take a step without orgasming, but even that release was denied her.

Knees quivering, barely able to stand, she bent forward with a gasp. In all her long, long life, she'd never felt anything like it before! It was - unbearable, unendurable! Her hands tightened into fists, then, with a furious snarl, she grabbed at her smooth, shiny sex and began stroking desperately. Hot, so hot!

Despite herself, her eyes closed, only for a moment.

When she opened them, Daring Do was stood before her. A fist grabbed her by the horn, and liquid flooded down it, coating her face, seeking and prying. Tiny, slithering tendrils crawled into her ears, then deeper still.

Nightmare Moon froze, her thoughts smothered, drowning under a sea of black.

Daring Do gasped hotly as Nightmare stiffened, her pupils shrinking to tiny points amidst the green of her eyes. Drawing back her hand, the liquid darkness rippled softly as it finished coating the other pony's face, then grew still, smooth and shiny and dry to the touch. Only her eyes and lips were left exposed, Nightmare Moon's towering body utterly coated in the shining, deliciously skin-tight material, like a living sex toy.

She knew she hadn't always felt like this. She knew she hadn't always found the sight of a coated, helpless doll to be the most erotic sight in the entire world, and she had to keep on top of the urges that were constantly bombarding her. Only Nightmare Moon was to be taken. She wasn't here to replace one tyrant with another.

But even so, it felt like a true, sincere pleasure of her own to take Nightmare's jutting, oversized breast in her hand and squeeze it firmly, seeing the entranced pony gasp mindlessly.

"You're my bitch, Nightmare. You're my slave," she told the motionless doll, ignoring the uproar above the shield.

"I am your bitch slave," repeated the dark queen, with calm emphasis.

"You're gonna make sure none of your former court try to hurt me. You'll make them stand down, and fight them if you have to. No hurting anypony too bad."

"I will fight any of them. I will protect you. I serve only you."

Daring Do couldn't help herself. She pushed her body against Nightmare Moon's, grabbing handfuls of her magically enhanced ass, nuzzling her head against the other pony's heavy breasts, licking and kissing. "Yes, yes, yes... you're my bimbo rubberdoll, you exist for me to fuck and use you."

Nightmare Moon, straight-backed, eyes blank, moaning thoughtlessly with every brush of her new owner's fingers, agreed huskily, "I am your bimbo rubberdoll. I exist for you to fuck and use."

"Again," gasped Daring Do, biting at her slave's jutting nipples. "Third person this time."

"Nightmare Moon is your bimbo rubberdoll. Nightmare Moon exists for you to fuck and use."

Daring Do arched against the enthralled alicorn, yet another orgasm exploding through her body with a speed and violence that left her quiveringly breathless. Fighting to speak, she managed to shout loudly, "The minute the shield comes down, you will free Celestia from her imprisonment!"

"Nightmare Moon will free Celestia from her imprisonment," echoed the towering mare. A fresh burst of shouting and struggling burst out on the terraces, as ponies fought to get away.

Letting her voice sink to a murmur, Daring Do breathed, "And when she comes back, you're gonna let her lock you and me away somewhere safe for a while, until she can fix this. But til she finds a way... we are going to be spending a lot of time together."

Author's Note

Another prompt generator pairing I wouldn't have come up with by myself, but I actually really like this one. I've always been interested in NMM's alternate reality, and there's a lot to work with, here. Especially if Celestia doesn't really get her tail in gear and lock up both of them before the suit's siren whispers manage to overcome Daring Do's personal willpower.

• Proofing by Djmill and JustTheBast
  Suggestions by DbzOrDie