A/N: This story was inspired by an original piece of crossover art by Telmand on DeviantArt - "Geralt vs Aliens", which I can't link to here, but can easily be found with a google search. A link can be found on my profile and a clip of it is used, with permission, in the thumbnail for this story. The fic is also being illustrated by the amazing Biblichor on Tumblr, who I owe a massive thanks to for her support.

While this fic combines elements of both the Witcher and Alien universes, it doesn't strictly speaking take place in either, and is more of a speculative reimagining of The Witcher in a scifi setting, in line with the original artwork that inspired it. I encourage everyone to find the painting in question and give it your likes and comments.

The blade sings. Chemically treated steel arcs through the air to meet the soft, fleshy resistance of a xenomorph egg, and slices through it as readily as a knife through butter. From inside, a facehugger stirs at its rude awakening, two of its limbs already severed and gushing thick green acid onto its surroundings, then it scrabbles to launch itself at its attacker.

A burst of flame from the man's hand stops it dead, charring it to a crisp, before another attack draws his attention off to his left. A whole facehugger leaps towards him, spindly legs splayed and tail wriggling while its mouth gapes in threat. He pivots, bringing up the same hand to twitch his fingers in a different sequence, and the creature is blasted back several meters as it's hit with the sign of aard.

There's a squeal and a squelch as it collides with the fleshy mass coating the floor, then more hisses sound from close to where it landed, the menacing black shapes of xenomorphs advancing through the dark.

The man looks on grimly. His yellow eyes like a viper's have no trouble seeing through the shadows, readying his sword as he anticipates when the next attack will come. White hair streams behind him, and there's a soft hum from the mechanism in his armour pumping alkaline oil to the blade, protecting it from damage from the fierce bite of xenomorph blood. Strapped to his back is another sword: silver, for all monsters falling under the magical class. The one in his hand: steel, for everything else.

A xenomorph makes the first move. It screeches, gallops, then lunges, claws scrabbling for his throat. Geralt dodges, pirouettes, then brings up his sword to punch through a weak point in its exoskeleton. It shrieks again: a sound that could be easily mistaken for a cry of pain, if he didn't know better. Now it's pissed.

Blood spills out over his hands with a faint hiss, but the alchemical augmentation of his armour does its job. He takes no damage as the creature rounds on him again, then another blast of ignii has it recoiling, scurrying away through the dark. Another xenomorph quickly takes its place, but Geralt came prepared.

A hand flies to his belt, clutching at a Dancing Star bomb and then flinging it towards the advancing horde. There's a flash, a sudden burst of heat, and then more shrieks as they scatter away from the flame. In the deeper parts of the cave, the nest starts to burn.

A grim look of satisfaction passes over Geralt's face. He's ready for the fight. The blade slices through the air, almost too fast to see, and three more fall. Still, others come to take their place, but he's expecting to slay a dozen or more by the time he's through.

After the first dozen have fallen, then the second, he's starting to worry he's less prepared than he thought.

The deeper he looks into the shadows, the more of the creatures come into view, and there's no sign of it slowing. He can't tell where they're coming from, not even with the potions in his bloodstream to heighten his senses, but still as they attack, one by one they drop. Dozens, if not hundreds, of eggs populate the cave floor, and as Geralt fights he takes the opportunity to drive his sword into as many of them as he can. His weapons and armor are becoming coated with the same organic mess that clings to the walls, though the advantage is that it provides more protection from the near-continuous splatter of acidic blood.

As the squelch of webbing pulls at his boots, making dodging ever harder, Geralt almost feels grateful for that. He bisects another egg, drives another xenomorph away with a stream of fire, then narrowly dodges a facehugger that gets perilously close to wrapping its tail around his throat. The small ones are just as lethal as the large ones, he's learned. And from the look of the pulsating eggs littering the floor, there's far more of them. His eyes dart round, specks of amber glinting in the dark, and tries to pinpoint the ovipositor that must surely be responsible for the abundance of eggs. If he finds that, he finds the queen.

By now, his fear level has crept up to hover closer towards panic than a healthy dose of motivation. One xenomorph he can handle. A small swarm is a challenge. An entire nest on his own is, as Vesemir once put it, suicidal. Geralt's starting to realise that wasn't hyperbole.

Another xenomorph lunges for him, and he drags his feet out of the sticky webbing they're sinking into and spins to bring his sword up in an arc. The acid-resistant alloy cuts clean through the creature's skull, alkaline blade oil working quickly to neutralize its blood, though not before a good amount has sprayed in Geralt's direction.

He throws up a hand and casts quen, shielding himself from the burst of fluid, but it barely buys him a second before the xenomorph's second set of jaws, intact and freed from the shell of its skull, extend and snap viciously at his head.

Even with it half-decapitated and dying, Geralt doesn't have a sign strong enough to repel it completely. He dodges the attack and rolls, uncomfortably aware of the squelching suction of the nest floor slowing him down, then rises and swings his sword to hack clean through the barbed tail swinging towards his chest.

He isn't getting paid enough for this. Terraforming companies want safe land to colonise, but they aren't prepared to pay a decent fee to the witchers who eradicate the threats. Not even prepared to give them adequate warning of the dangers, Geralt thinks bitterly, as he recalls that the nest had been described to him as a "minor" infestation. If this is "minor", when he makes it out of here, he's demanding a minor fucking payrise.

Another attack, another dodge, followed by a counter-attack then avoid-the-acid-spray, and Geralt's starting to feel the drag of exhaustion. His chest heaves, each swing of his sword getting heavier and less precise. He can tell his signs are weakening, too many of them cast together in quick succession, and the difficulty of maneuvering through the nest is depriving him of his speed advantage. He reckons he's been fighting non-stop for near thirty minutes by the time the sound comes from above: the characteristic hiss of a xenomorph and the menacing snap of heavy jaws. Just from the sound, he can tell it's unmistakably larger than any of the drones.

Geralt turns his head upwards, and sees what he came for.

The queen shrieks, lowers her crested head towards him, and the witcher twitches his fingers and casts a stream of fire in her direction. Satisfaction tugs his mouth into a smile as he hears the responding screech of distress, and she recoils into the ceiling. If he kills the bitch, the others will drop far easier.

"Come on," he growls, and the queen appears to rise to the challenge as she spits then goes for him again, a downward swipe of her claws towards his throat. Geralt rolls out of the way, slicing through another egg on his way back up, though the stickiness of the webbing tries to pull him back down. He lets off a burst of low-intensity fire at the floor to try and weaken the chemical bonds, then drags himself out with a creaking snap of the organic fibers before swinging his sword in a wide arc that deflects her claws and takes out a xenomorph not far behind.

Then he missteps. All it takes is one instance of bad footing, and his boot sinks into the fleshy substance up past the ankle.

His stomach lurches. Jaws descend from above to snap close to his ear, and it's only his heightened reflexes that allow him to twist away in time. His sword swings, hacks off the extending tongue housing the queen's inner jaws, but his foot holds fast. He's stuck.

Shit.

Another screech behind him, and Geralt ducks, arcing the blade over his head so a spray of acid would rain down on him were it not caught by the golden glow of his quen shield. That's losing intensity. He needs to recast, but his energy for it is running low.

Opting instead to expend that energy on the offensive, Geralt casts ignii and drives away two more. He keeps the fiery glow alight in his hand, a warning should any more of them try to advance, but it's not enough deterrent to buy him time to break free. One of the bolder ones goes for him again. It takes a burst of fire direct to the face, rushing forward in defiance, then a last minute switch to aard takes all of Geralt's concentration to knock it back.

Facehuggers scuttle across the floor. One of them leaps at him, and he swings his sword like a club and splits it in two. Seconds later, another meets the same fate. Anchored in place, he can't pivot in time to avoid a third.

There's a soft hiss from above him, and it almost seems like the queen is laughing as Geralt sees the pale, spidery shape drop down from the ceiling just a heartbeat too late to stop it.

Abruptly, his breath catches in his throat as something slick and bitter invades his mouth. He struggles, a mad, ten-second burst of panic as his sword falls from his hands and he claws at the creature attached to his face, then the shock takes over. Geralt's body falls limp, and he feels nothing more.