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It was meant to be a simple mission. Land on an uninhabited planet, take a sample of the local flora, return to the Mothership so that they could study it and see if they could harness its properties back home.
The Mothership is where most humans have grown and lived. His planet (a sort of psuedo-earth after the First Earth colony was being repaired due to extensive global warming damage) was more of a hub for the hundreds of intergalactic alliances they've made over the years. Izuku has never been, but his dream job means that he strives to provide as much scientific discoveries as possible!
So, Izuku’s homeworld was interested in this planet as a sort of… side project. Another notch in their space academy's belt. The glow beneath the atmosphere caught their eye like shining diamonds underwater, and Izuku was one of the scientists just high enough on the corporate ladder to get sent to the surface.
His team had split up to cover more ground.
Izuku had been excited— his first ever on-world experience! Every experiment he’d ever had was onboard a ship— and now he was tramping through thick, spiraling jungle with his own two feet. It was incredible!
Until, something solid and smooth had knocked him down into an outcropping of jagged stones and moss-like material.
Izuku goes tumbling ass over head, down down down until he lands hard enough that his suit signals its damage with an affronted 'beep' before it begins repairing itself.
Izuku winces as he feels the material seal against his skin again, the rip repairing before he even recognizes where it was. It's darker down here, enough so that his eyes need a moment to adjust.
It’s as if a small part of the planet swallowed him whole, the stones like teeth and the moss like a tongue. It wobbles forebodingly as he shifts his body where he landed so heavily in the middle of the cavern, like the liquid dirt of quicksand.
It doesn’t attempt to suck him in, though, and Izuku is left to juggle his wrist-brace and his aching ass, to click on the rinky-dink flashlight that was issued to him. He had a better one in his expedition bag— but it had gotten snagged on a ledge on the way down.
The strap is unfortunately holding steady, from Izuku's angle. It rocks slowly with the momentum, to mock him.
And Mothership hadn’t issued them jetpacks for this trip. There was no need to spend the extra money, or so they’d said.
So now Izuku was stuck.
“Great.”
He's lucky, at least, that he didn't need his helmet— also still strapped to his bag. The air on this planet was suitable for humans, so Izuku had been free to breathe in a different atmosphere. His lungs tingled with it, as if just a hint of mint coated the oxygen.
But he's getting distracted— he needs to figure out a way to get help quickly.
Izuku pauses to catalogue himself, to be sure he didn't actually break something. But the moss is tenderly soft, almost like a blanket. Some spots look woven, even, as if it was gathered and placed in this specific area for something. Naturally? Or, some sort of organism utilizing it as part of some sort of nest…?
Izuku rubs his finger along a 'seam' in the moss. It's wet with something smooth and shiny, clinging to him like a stubborn spider web.
He hopes it isn't corrosive as he wipes his hand clean on his thigh— his space suit thin enough that he can feel as the wet cools, but thick enough that the fluid (whatever it is) doesn't soak into the synthetic fibres.
Something slithers in the darkness.
Though he's a scientist, Izuku has never seen a real snake before (for most are endangered and living in the most suitable environments on New Earth so that they can repopulate). But the sound of something smooth and thick being slid across foliage immediately brings to his imagination a leviathan-like serpent. It was hardly a small sound, either.
Izuku feels as though he turns to stone. He’s terrified all of a sudden, the feeling creeping up against the back of his brain before it clutches him and drags him under the full effect of terror.
Izuku doesn’t turn around, but he can hear breathing behind him. Made purposefully loud, through clenched teeth and a drooling maw. Spittle splatters onto the moss, a harsh drip-drip-drop compared to the almost gentle breeze in the trees some dozen feet above Izuku's head.
The air doesn't reach down here, especially with how the hole is partially overgrown, well-hidden. There's no discernable escape for him.
Izuku can only sit there, his legs turned to limbless jelly and his heart kicked into overdrive. He just stares up at the waning sunlight as the cavern gets coated in more dark.
Rendezvous was meant to be in two hours, just before the sunset. Izuku had been following the light, eager to drink in the sights and sounds as much as he could.
And now he was stuck.
“You scared?” The thing behind him grunts. “I can tell you’re frightened, little creature.”
The voice is human, in a way, but the tail that wraps around his waist is decidedly not. It’s thick and smooth, like a sort of prehensile marble— snake-like— and Izuku’s reflex is to slip away, to make himself distant so that he can first try diplomacy before he next tries to scale the walls to make his escape.
But he can’t move.
Physically can’t do anything beyond shakily breath and blink even as he tries to so much as twitch his pinky finger.
He panics. Anxiety eats through the months of training provided to him from Mothership, and tears build up against his lashes before they get weighed down and spill down his cheeks.
A hand— huge, large enough to cover his entire face almost twice— cups his chin. To gather the tears before they can soak into the blanket-soft moss beneath him.
“Save your strength, little one. It’s been so long since I’ve found a new toy.”
Izuku’s head is turned to the side, and from his peripherals he can see the creature with which he’s been trapped.
He’s huge, as his hand hinted. Deep orange, kind of like a pumpkin. Izuku would think it was a pretty color if it wasn’t so frightening right now. In any other circumstance, he’d be excitedly rattling off questions about the creature’s biology, diet, social hierarchy… Anything he could think to learn more about this new species— because Izuku has never seen anything like him. The planet was meant to be uninhabited, according to the locals in this solar system.
The creature is mostly long limbs and a pretty face. A slender upper body, with thicker legs to hold up the long, prehensile tail that has yet to let Izuku go despite the fact that he can’t move. Shit.
His head is twisted more as the creature comes closer, until his neck pops in a way that makes his body jump with the pain.
The alien makes an interested noise at this, and then he is all that Izuku can see.
His face is pretty. Red eyes beneath long lashes. Full, plush lips that look soft despite the number of scars that line the monster’s chest, stopping just beneath his chin. Eyebrows that furrow as he regards Izuku, the same color as the starburst of hair on his head. And a nose that scrunches up when Izuku keeps crying.
“You’ll do,” the creature says, eventually. His words don't match the movements of his mouth, but Izuku hears the Japanese clearly, without his automatic translator. “I’ll take good care of you from now on, my pet.”
“P-please don’t hurt me,” Izuku stammers, trying valiantly not to stare into the luminous red eyes staring back. They’re hypnotic, swirling in the dark, and Izuku is too far from his comm links to signal for help. He’s truly alone.
Well… alone with—
“Katsuki.”
‘Huh?’ Izuku tries to sound, but his throat stops paying attention to him, just like the rest of his body.
This is planned, by the way Katsuki’s look grows even more smug. His teeth shine even in the cave shadows and— oh… so does the rest of him. It’s brief, but a flash of color belies Katsuki’s excitement.
“My name. Remember it, little one. It may be the last higher thought you’ll ever have.”
Izuku shivers, but doesn’t get a chance to retort.
Sharp talons wrap around his neck, all the way around, and if Izuku breathes in too deep, he’ll be punctured by them.
But they don’t maim. They push him down flat on his back, and Izuku goes obediently— if not unwillingly.
They’re even gentle as they cut through the titanium-grade suit (issued to him also by Mothership, of course. Virtually indestructible, self-repairing… like paper, compared to these talons), and leave him fully bare.
Most of his suit stays covering him, trying valiantly to repair itself from the extensive damage, but the important parts are exposed.
His cock, soft and harmless-looking, lays against one of his soft thighs. His chest catches Katsuki's attention briefly, and his hand passes over both nipples at the same time before he twists Izuku so that he can make sure his entire ass is exposed as well.
The rest, he leaves covered.
Izuku's sweat catches at his neckline, which is positioned where his jaw meets his chin. His toes wiggle, because he's uncomfortably aware of them now that they aren't sealed in the skin-tight material. It was meant to adhere to him better than a second-skin, and now it was loose and weird.
Izuku can’t hide himself as the creature— as Katsuki looks him over like produce on a market stall. He’s partially lifted by one hand as Katsuki counts the freckles that haven’t ever been seen by another living creature, and he thumbs across Izuku’s shy cock that jumps to life without his permission.
“Good boy,” Katsuki praises. "Already so responsive. Will you keep being good for me?”
Katsuki doesn’t bother waiting for a reply. He lets Izuku’s legs drop, and then he’s pulling back to flex his hand.
His talons fall off, and Izuku mentally screams when they bounce against his belly before they slide off to the side. They don't puncture, though they had looked like daggers coming to stab him.
When Izuku focuses upwards on the hand again, Katsuki is concentrating. His curved appendages pop and snap alarmingly— and then they straighten out like rods.
His fingers begin to drip with something clear, slick and soft. It’s… lewd, kind of like pre-ejaculate?
Exactly like the stuff that Izuku had stuck his hand in earlier. Oh.
It gets worse when Katsuki advances upon him again, an eager look on his handsome face, now. His new fingers are cool as they slide up the exposed part of Izuku's skin, catching at the bunched up edges where Katsuki's ripped through the suit.
He leaves trails of the sticky, clear… stuff behind. And it's as if though paths heat up over time, leaving Izuku aching for some sort of relief both outside and… and i-inside. Oh beings above, his cock was so hard.
Izuku isn't sure what he was expecting Katsuki to do to him, other than perhaps eat him whole (being's above, he's large enough to try to do so). But to… touch him like this? To leave him so suddenly wanting with no way to soothe himself? It's violating— it's maddening, it's— it's….
Another hand presses against his hip. The nails on that side slowly slide into Katsuki's own skin, receding until his fingers are bare. More things made safe to be stuffed inside of Izuku’s forced-pliant body.
All he can do is make a soft noise of protest via a huff out his nostrils as Katsuki nudges two fingers up against his bare hole.
Katsuki ignores it and slides them in one at a time. His skin texture makes the slide sinfully easy, as if they were meant to be up there in the first place. Izuku hadn't even been properly stretched first.
And without anything making the experience painful, the only focal point Izuku can cling to is the infuriating pleasure that cuts through him when Katsuki aims at his prostate and plays with it to watch how Izuku’s body reflexively tenses and flexes with each pass even beyond the numbness.
Izuku is out of control of himself— and it’s so scary but fuck— it feels so good. He has, of course, touched himself before but… no one else has. He's never had such an angle to work himself over with, even with toys designed and curved to do just what Katsuki is so casually doing to him.
Katsuki rolls him over onto his side, lifting his leg by the thigh so that he can keep fingering him open, and Izuku gets to watch as Katsuki’s cock throbs where it hangs heavy and full between his legs. Another part of him so humanoid but so… not.
The tip itself is much rounder than the human penis, less of an obvious shift between the glans and the shaft. Just a small crinkle of skin that gathers and drips what must be Katsuki's equivalent of precum. It's thick, though— again, the same stuff coming from his fingers.
Katsuki is lubing him up for it, Izuku realizes all at once. A small mercy, perhaps, because his cock couldn't fit inside him under normal circumstances. Not if Katsuki wanted a living plaything, anyway. Izuku's hips already ache just from the two— oh, no, he slipped another in while Izuku was panicking— three fingers prying him open.
Katsuki notices him watching. He flexes his belly, a clicking sound resonating from his throat before he huffs like Izuku did just before he found himself being fingered.
It's a mockery, maybe? Or perhaps Katsuki's natural way of communicating? Which— how did he know Izuku's language anyway? Their translators weren't all encompassing of every alien language, and surely he was too far from his communicator for it to pick up in his earpiece anyway.
And why did Katsuki wish to speak with him anyway? Just to tease him for being caught so easily in a trap? Did Katsuki purposefully get him in this position? How is he going to get out of this? Does his team even care—
"You think so loud, little one," Katsuki grumbles. "Focus on me. Look at what you're doing to me."
Izuku is still paralyzed, so he can only hazily blink as he watches color pulse up and down the length, starting in a small circle just beneath the ridge of Katsuki’s… cock, though it looks more monstrous than that. The pattern continues all the way down to the base, then across the rest of Katsuki’s body.
"I heard the noise you made when you fell," Katsuki purrs, the timbre like a melody as he gets closer to Izuku. "That surprised yelp as you so suddenly found yourself in my den. So sweet. I want to hear more of it— maybe you can let me hear it without another shove."
'Another shove'. Izuku had been pushed down.
"Your eyes are so pretty when you use your brain," Katsuki says. "I can't wait to see what they'll look like when your pretty head is empty."
Izuku squeezes his eyes shut reflexively, and Katsuki laughs. The sound is punctuated with that clicking sound again. Izuku's body goes more limp, somehow, obeying Katsuki's whims now.
With his eyes closed, his panicked tears well up more easily and mix with the drool that's beginning to spill past his lips.
"Look at me."
Izuku's eyes open. Katsuki's cock has thickened with his arousal, and it makes Izuku want to weep. It'll break him.
He wants to taste it.
The markings look near imperceptible compared to the rest of Katsuki’s skin, but the more he's gotten aroused, the more they filled with deep, swirling color. Natural, self-regulated bioluminescence in a non-marine organism is a bit rare from Izuku's studies. In any other circumstance, Izuku would have squealed in excitement and grabbed for his datapads.
But he gets distracted, because Katsuki is glowing in the dark, casting Izuku both in shadow and tingling orange and white. It’s as if someone had popped a star and spilled it in Katsuki’s bloodstream. It burns in a way, just barely like the air on this planet, and Izuku isn’t sure if it’s the paralysis that’s making it not hurt, or if he’s just imagining it all himself.
“Open your mouth,” Katsuki’s voice echoes through his ears.
Izuku’s mouth drops open, tongue gathered on one side of his mouth because Katsuki hasn’t let him lay flat yet.
“Good Deku,” Katsuki purrs, and it’s as if he’s been blessed. Euphoria travels through him like thick wrappings of silk, until he suffocates in. it. He hates it— loves it so much. Feels so good. Kacchan, more, more—
Red eyes take up his vision, like guiding stars. Izuku’s own eyes dart between them until he gets dizzy.
Katsuki looks away for a brief moment as he wiggles his fingers as deep inside as they can get. The red doesn’t shine as bright at that angle— it’s not enough. He needs it— he needs—
“More,” Izuku strains through his uncooperative throat. “M-mm… mmph!”
Katsuki’s dirtied fingers nudge into Izuku’s open mouth and he’s made to clean them. Katsuki’s natural lubricant is just another thing for Izuku to get addicted to (the first: his eyes), and his brain tingles as he swallows it down obediently.
"That's a good pet." Katsuki's fingers are rough as they fuck Izuku's mouth, though the praise makes it all taste sweet.
It's… really good, actually. His tongue seems to wake up as he gets a taste, and he bears his lips down against Katsuki's knuckle so that he won't pull away before Izuku cleans what is gifted to him.
But Katsuki pulls it away despite his best efforts, fingers only partially cleaned, and Izuku is empty. Empty and needy and all that's left is the aftertaste of that yummy gift that his master left behind.
"Mm…" Izuku begins, but Katsuki gathers behind him before he can complain and whine for it again.
It gets a bit fuzzy. His knees get tucked beneath himself, angling his ass upward so that Katsuki doesn't have to lay so flat to get a good angle. Then a large hand is cupping one part of his chest, so that Katsuki can get a good grip on him. His other rubs a wide circle around Izuku's fingered-open rim.
And his tail holds him steady around the middle, just so that Izuku is surrounded entirely by his Kacchan.
Izuku's mouth feels tingly, like the tiniest of explosions in his mouth. He holds his mouth wide open so that the feeling doesn't overwhelm him, but that just means the needy noises pulled out of him can't be muffled. Oh, well. Izuku could hardly think past how heavy his tongue was in his mouth now.
He wanted to swallow, to gather up that layer of precum that Kacchan had painted his mouth with, but all he could do was let it mix up with his drool and feel it drip down in long lines out his mouth as he panted. What a waste. He wanted more.
Katsuki slides into him.
Izuku's eyes roll, eyelids fluttering, eyelashes clumped with tears. It's too much. He'll break— he didn't get stretched enough for this, did he? Katsuki is gonna break him!
Katsuki doesn't stop until every inch is buried inside of the warm, prepped hole waiting for him.
"N-no—!"
"Taste me," Katsuki orders.
And then his fingers come back, encouraging Izuku suckle them dry. When he obediently sucks hard, it floods his mouth and goes down his throat so easily. Especially when Katsuki tips his head back so that his loose lips won't keep spilling.
Izuku moans.
Kacchan grinds his hips against Izuku's ass, groaning from deep in his chest. Blearily, Izuku can see the glow of his eyes even with his unseeing gaze. They threaten to drown him more than the slick he's being willingly fed.
More, more, more.
His cock is so big. It aches, kind of. But muted, in the background— a bit more when Izuku wags his hips from side to side to see if he can get any more of it. But he's already taken all that Kacchan has to give— which is a lot.
It's apparent by the way Katsuki's tail ruts against the bump in Izuku's tummy from beneath his skin.
Kacchan says something, but it gets lost between Izuku's own moans, and the endlessly repeating 'MORE MORE MORE MORE MORE' in his head.
Izuku doesn't know what he wants more of, as it stands. But… but Kacchan does, doesn't he? He was fucking him faster now, his cock (it's so biiig) pulsing inside of him.
Katsuki pulls his hand away, and Izuku's lower half drops flat against the moss. He grunts on impact, but it's more reflexive when that makes Kacchan's length just pass even harder across his prostate. Izuku would go crazy if it wasn't for the present that Katsuki left in his mouth. It's so yummyyy…
He wants more.
Izuku's fingers crawl beside his face, and then dig into the moss-nest so that he doesn't get shoved all the way across it with how hard Kacchan is fucking him.
"There's my good pet. Does it feel good, Deku?"
Deku… is that him? He's Deku, right? He's Kacchan's good pet…
He nods desperately. "I'm… 'm g-good… More…?"
Kacchan gives him more.
He lifts him almost clear off the ground, just enough so that gravity can do most of the work as he uses Izuku's body like a toy. It's so gooood, being Kacchan's toy. Being his pet. His— his Deku?
Deku cums at the thought, thighs clamping together with an audible smack.
Kacchan huffs out a soft laugh, but lets him stay in that position. It's harder on Deku's shoulders, his entire weight being held up by them and Kacchan's hands wrapping around his waist. But that's okay— he didn't mind the pain. Kacchan was gonna cum— gonna fill him up. That's all he needed.
"That's right. All you need is Kacchan's cum deep inside in you. Isn't that right?"
Deku pants harshly, and his mouth does that tingling thing again. It's less strong now that he's swallowed down most of his treat— fuck.
"Take every drop," Kacchan demands. And Deku obeys— is this the 'more' he's been wanting? To get filled with Kacchan's cum? That sounds… so good. He wanted it. Kacchan's cum— Kacchan's cum inside him.
"Cum in me, cum in me…!" Deku doesn't know how to say anything else beyond that now, but Kacchan is so good to him.
He wraps his beautiful hands around Deku's neck. Squeezes a bit, bearing down to shove Deku back flat against the moss so that he won't move out of place.
Then he cums, just like he promised. Deku feels it flood his belly, warm and wonderful and perfect.
Kacchan moans for him, glowing brighter. It's so pretty, and the light that casts on Deku makes him warm up. Like his own personal sun. Kacchan was so good to him.
His cum fills him up so fast that it hurts, just a little. His belly swells with it. Kacchan's tail doesn't move from where it's firmly wrapped around his middle, so Deku can see how his tummy distends a little around it, and then Kacchan's tail shifts lower so that he can help him hold it all inside.
Deku moans to thank him, because that's all he can really do beyond his eyes rolling up into his head and his mouth falling open again. He was so full— but so empty at the same time. His mouth was so lonely… all he had left in it was his own spit and the memory of Kacchan's fingers.
Kacchan is still cumming. Even when Deku's body loses strength and goes limp all over again, without Kacchan's help this time, he keeps cumming. Deku gurgles as his body responds aptly, shuddering in pleasure as his own forgotten cock spurts out another orgasm without either of them meaning it to.
Deku feels a mess.
The upper half of his face coated in tears, the lower half in spit. His belly so full that it has ripped at his suit even more (undoing all that useless work it had done trying to rebind its own fibres around his stuffed taut belly), and gone pink where it had stretched too much too fast. And red, where Kacchan's cum sits inside of him, still glowing like embers. His own cock, aching as the tip of Kacchan's tail leisurely plays with it, as if to see if it can get him to cum again before Kacchan has finished.
He will, if Kacchan wants him to. Anything to get more. He's going mad without it. Everywhere on his body feels itchy, tingly… empty.
Deku starts crying again, but Kacchan gathers him up with his perfect hands and twists them so that they're face to face.
Is he still cumming? Izuku doesn't know anymore.
There's a familiar beeping sound in the background. A familiar voice calling out.
'Midoriya, we have a lock on your coordinates. Help is coming.'
Cumming? Is he still cumming?
Deku doesn't know anymore.
Anymore… more..?
More?
"Shh, little one." Kacchan unravels his tail from around Deku's middle. "You hear that? Your people are coming for you."
"C-cumming…"
Kacchan laughs.
Gentle thumbs circle his cheeks, wiping away some of the mess he's made of himself. Kacchan kisses the dry spot, a simple peck, and Izuku twists to try to capture his lips for himself. When he misses, he ends up closer to his thumb— but that's okay. It'll taste so yummy.
Kacchan teases him by letting him lap at the very tip of it, and then pulls it away. He sits up on his knees, tugging his cock out of Deku's spasming hole. It clamps down valiantly after being fucked open so hard, but Izuku is so relaxed that it begins to go pliantly soft again.
"Oi, didn't I say not to spill a drop?"
“Hnngh—" Deku gasps as Kacchan shoves his fingers in, to quell the flow of thick, sparkling cum trying to escape from him before Kacchan is able to fill him up again. Izuku likes glowing like this, so he tries his best to stay tight and keep it all in, too.
"What a bad pet. Gonna have to replace what you wasted. I hope your people are the patient sort," Kacchan teases.
Deku cuddles against the tail that sweeps his sweaty hair from his face, and then curls around the back of his neck to support him so that he can look down between his legs.
Kacchan's cock is hard again. Or, didn't get soft in the first place? Kacchan was so good to him.
“Guess you’re gonna be my little, personal cumdump from now on. You like the sound of that, Deku?”
The nickname makes Deku's cock drool against his rounded, glowing belly. It's said cruelly, like a teasing joke. But that's his name, isn't it? Kacchan said so.
His eyes cross at the sudden thought of Kacchan entering him again. His mouth was so lonely, and now so was his ass.
“W-want… Wanna feel your cum,” Deku whimpers, head lolling as he succumbs. “I’m so emptyy, please Kacchan, more— oh!”
Katsuki fucks into him with one rough thrust, and Izuku is lost. The only thing that remains is Kacchan’s new, mindless fuckdoll.
And Deku can’t remember ever wanting it any other way.