Chapter Text
Sonic thought he knew his rival.
Well, he thought that he knew Shadow well enough. While he understood Shadow was an artificial hedgehog, he was vaguely aware of Shadow having alien DNA injected in his bloodstream. It's not something everyone brings up often, so Sonic's mind doesn't ever sit on the topic for long.
He never thought about what it might actually entail.
He doesn't even really know what triggered it. He and the dark hedgehog had been burning daylight by sparring like usual, preferring to let their fists and kicks do the talking. Shadow seemed no different than his usual brooding self but Sonic felt something strange fester in the air around the other hedgehog.
Shadow's chaos energy was so strong, that Sonic's other senses could at least faintly register it. But this sensation was entirely different. More tingly, somewhat more static, and even a bit foreboding. It made the fur on his shoulder stand on end. Sonic overlooked it in favor of getting down to business. That was his first mistake.
His second was ignoring the strange scent of what he could only describe as burning rot. He thought that it was just some animal that had died in the forest nearby. But the pungent odor persisted. Even stranger that it seemed to be clinging to Shadow himself the more they fought.
Next thing the hero knew, a loud, piercing roar assaulted his ears, causing him to pin them back against his skull in response. An ebony blur flooded his vision before he felt his back collide harshly with the dirt.
He let out a pained whine as the air was forcibly knocked out of his lungs, but he was given no time to recover as something moist and slimy constricted his wrists and pinned them beside his head while another pair had slinked around his calves. An inky black shadow cast over his body as something big hovered over him.
Sonic's senses returned to him and his vision cleared. His eyes widened as his gaze was returned tenfold by multiple pairs of blank, glowing red eyes. Sonic gaped as a black amalgamation vaguely in the shape of a squid hovered threateningly over him.
Sonic the Hedgehog is a hard guy to scare. He's faced eldritch abominations that completely eclipse his measly hundred centimeter height with nothing but the straps on his shoes, a cocky grin, and an attitude big enough to compensate for his stature. He's pummeled the ever loving shit out of god-like beings without even remotely fearing for his life.
That being said, Sonic was fucking terrified at the moment.
The creature's low growls filled the tense atmosphere as Sonic struggled against the tendrils holding him in place. The blue hero flinched as a wide slit appeared beneath the monster's eyes, revealing several rows of serrated fangs, allowing dubious black liquid to drip from its mouth onto Sonic's cheeks.
“Sh-Shadow?! Hey! You alright, bud?” His only response with more deep growling as the creature eyed the young hedgehog's prone figure up and down.
“Come on, Shads! You win, I get it. Y-you can let me up any time now!” Sonic chuckled nervously. Whether it was to placate himself or the abomination leering at him, he wasn't sure.
Shadow had to be in there somewhere. For the most part, the older hedgehog was the epitome of cool and collected. But THIS thing? This thing looked like it didn't even recognize Sonic. In any normal instance where Shadow had managed to kick his ass, the other would at least help him back up to his feet before gloating in his own way.
But this version of Shadow had no intention of letting Sonic run off. Its hold was iron tight. The poor hero could feel his blood circulation cutting off in his limbs where the tentacles held him. Struggling did more harm than help, forcing the speedster to sit and wait for the creature's next move.
For a while, it hadn't moved. The thing just stared blankly at him, with no expression for Sonic to discern. Its growls began to trickle to a low rumble as it continued to observe the small hedgehog. Was it hungry? Was it deciding whether or not to eat him? Even without any visible pupils, he didn't like the way this thing was looking at him.
“Hey, bud, trust me. I don't taste good!” The hero tried to jest, ignoring his own thundering heartbeat echoing in his ears.
The alien ignored him. Instead, it lowered its head to lean into Sonic's. The blue speedster froze. Surely the creature was going to end him. Shadow didn't seem to be home. It was just Sonic and this monstrous blob.
Something long and wet drags across the side of his temple.
Sonic gasps at the sudden uncomfortable sensation. It happens again. And again. It takes a moment for Sonic to realize the damn thing is licking him. Was it … actually trying to taste him, perhaps? He was speechless as the alien simply licked the side of his head, matting his quills together with its slimy saliva. The hero cringes at the sensation. The amorphous creature repeated the motion several times across his temple, moving to lick his forehead, leaving stringy black fluid trailing with each lick.
“Eugh!! Come on, man! Gross—”
The young hero tried to pull away from the intrusive tongue, but was met with more tentacles shooting out of the creature's body to hold him in place by his hips. His situation was getting dimmer. No escape, and no way of understanding this thing's intentions. Until he was given an opening, he had to keep this cool and make sure he didn't piss Shadow(?) off more than he probably was inside whatever the hell he just transformed into.
Suddenly, there were slimy tendrils running across his sides. Sonic let out another gasp as disgustingly smooth appendages ran across the opposite direction of his fur until they reached the generous swell of his chest. There was no way this was happening… This creature couldn't have known what it was doing. The hero groaned as wet tentacles circled each pec and squeezed curiously at an agonizingly slow pace.
Instead of licking, the alien had changed its tactics to rubbing its head vigorously against his own. It's growling had diminished completely and instead made curious trilling noises. Sonic let his body go limp as best he could to avoid hurting himself while this massive blob jostled him in its hold. But tension quickly returned as he felt moisture gather around his left nipple as peach fur was pushed aside to expose the small bud to the open air, allowing it to harden from both the cold and the disturbances.
“N-nnh?! Wait…”
Sonic's thoughts were getting muddy. He faintly registered that one of the tentacles had morphed around his areola. He squealed as the thing started sucking at the stiff bud. At the same time, the head of the creature stopped nuzzling the side of his head in favor of shoving itself against his neck and shoulders. The hero whined helplessly as the sucking sensation on his chest grew stronger. Almost painful, even.
The most embarrassing part about it was that Sonic could feel himself getting wet.
He whimpered as his groin stirred with interest as his chest was pushed and squeezed. His cunt twitched as he felt slick building up within its confines. The alien trilled again as it nosed heavily at Sonic's shoulder. He inhaled sharply, a jolt shot down his spine when the alien's wet tongue began slobbering all over his neck.
The monster let out a series of high pitched clicks from where it had shoved it's noise in the junction of Sonic's neck and shoulder. It was the only warning he received before feeling sharp pain blossom as jagged teeth sunk into a chunk of his flesh. The hedgehog yelped as it latched on relentlessly, his minor thrashing only served to help fangs sink further into his skin, soiling his fur with both slime and blood.
It purred and cooed while leaving odd trails of slime wherever it touched, rendering Sonic's body a filthy mess as questionable material clung stubbornly to his fur. Sonic groaned about how hard he'd have to scrub himself later once he got out of this mess, but he wasn't allowed to sit on the thought much longer as something sticky began creeping along his inner thigh, stroking at his soft leg fur. There was no way…
“Shadow, wait…”
The creature ignored him. The oozing appendage continued upwards towards Sonic's trembling pussy. On instinct, he tried to slam his legs shut only to be reminded that the alien jammed his legs in position. Open and vulnerable. Free for the taking. Sonic's heart thundered in his chest as he felt the slim tentacle slide against his moistened slit. He moaned as it simply slid back and forth between his pussy lips, the motion made easy by both its own natural slipperiness paired with his slick lubing up his labia.
“Nnh! Nnngh… aah…”
His cheeks reddened at the sounds coming out of his own mouth. The monster didn't let up and seemed egged on by his needy sounds. The tentacle decided it had waited long enough before probing past pink folds and wasting no time bullying itself into Sonic's hole. The hedgehog hissed at the odd sensation, his body trying to adapt to the new intrusion. Sonic hadn't been able to get a good look at it before, but he could feel how thick the appendage was as it squeezed its way into his walls.
“Aahhn, w-wait ah Shadow…. Please…”
His cries were left unheard as his pussy clenched around the intruder. He felt his hole spreading to accommodate the large appendage as it delved further and further into his cunt. Sonic let out a high pitched whine as there seemed to be no end in sight. It just kept going and going. His poor hole was getting stretched to painful lengths. Thankfully, just as it seemed like he could take no more, the tentacle stopped slowly.
He let out another whimper as the alien had seemed content to rest it inside him, letting it laze around in his tight hole as Sonic's groin started getting sore. Sonic sighed at the slight reprieve, but his muscles did not relax as his whole body remained rigid. The grimy tentacle began slowly retreating from his warm heat after a few minutes of stagnation, dragging languidly against his softened walls. His legs trembled in the monster's hold as he allowed himself to let out the breath he did not realize he'd been holding in.
Nothing lasts forever. Sonic's body was rudely jolted as the alien tentacle was thrusted back into his heat with brute force. His moans reached pitches he thought were impossible as his pussy was mercilessly pounded at a break-neck pace, in and out, sending his small body forward with each thrust.
Rivulets of slick dribbled down his thighs as the girth tentacle spilt his fluids from sliding in and out. Vaginal fluids drooled sloppily from the crevice where tentacle met pussy. All Sonic could do was whimper as lewd squelches and his own obscene noises filled his ears. His hips unconsciously began moving in tandem. He could barely hear the purrs of the creature above him over the volume of his own squeals.
“Please… a-ahh please!”
He didn't know what he was begging for. For it to stop? Hurry up? Slow down? He wasn't sure. His whole world was tilting on its axis as the tentacle curved up and slammed against a particularly sensitive nub. He cried out over and over, falling on deaf ears each time. He never felt so humiliated, he's never felt this good.
His own fingers couldn't reach this deep, and he's never been this brutal with himself. It was thrilling. It was dangerous. His eyes rolled to the back of his head, his spine arches in time. with a particularly harsh thrust.
“Ahgh! Mmhh, Shadow~!”
His gut was burning. His heart was ready to burst out of his chest. The monster had been lapping at the dried blood crusting over his shoulder, its roaring purrs sending vibrations across Sonic's neck that tickled. He felt the raging inferno within his stomach threaten to consume him alive. The alien went back to nuzzling the side of his head in what could have been seen as a comforting gesture. One that Sonic couldn't fully appreciate in his delirious state.
“Shadow, stop ahh I'm NNHH-no I'm gonna—”
Instead of stopping, the creature trilled happily, as if to encourage the inevitable. His hips snapped as the creature decided to thrust deeper than previously. His throat became sore as he screamed his lungs dry. His cunt begged for relief from the torment. It demanded release. With one last wail, he contracted his muscles, allowing a generous flow of vaginal juices to gush from his pussy. He whined at the uncomfortable sensation as his fur matted around his crotch from the disgusting mix of his own gunk and alien lube.
His chest rose and fell in the aftermath. His body finally relaxed for the first time since being pinned down. Even the alien seemed to be done as the tentacle began withdrawing agonizingly slow. Sonic shakily whimpered as he heard an obscene wet pop before feeling hot fluid lazily flood out of his hole onto the dirt beneath his ass. His body practically screamed “no more.” He felt the monster's hold on his wrists, calves and hips loosen, but he was too groggy to even fight back. He simply closed his eyes and flopped back on the puddle of his own sweat, cum and alien residue. He hadn't noticed the sudden shift as black slime melted away to reveal a much more familiar figure.
“F… Faker…?!”
Emerald eyes snapped open. He shot up into a sitting position, ignoring his body's vehement protests. His mouth gaped at a certain black hedgehog staring back at him with narrowed scarlet eyes. The shame did not catch up to him until a few moments later. He wanted to hide away. He didn't want Shadow of all people to see him like this. He wanted to curl up and sink into the floor. But more than anything, he wanted answers.
“Shadow…” His own voice startled him from how raspy it had gotten.
It seemed Shadow didn't hear him. The ebony hedgehog stared at him with what could only be described as pure fucking horror. He was clearly in disbelief as his eyes locked onto the state of Sonic's body. He then glared at his own hands as sticky black fluid dripped down his arms with a clear rage that Sonic had only ever seen once…. And it was when Shadow was still hellbent on revenge.
Sonic tilted his head. He tried to get up to approach his rival, but his muscles refused to cooperate, simply too tired and spent. The action brought Shadow out of his stupor and he stared back at the limp blue hedgehog in terror. Sonic had reached his hand out to the elder but, in a flash of gold, the other had sped away, leaving him alone with nothing but his own thoughts.
“Shadow! Wait!” He called out to empty air.
_____
Disgusting.
He was disgusting.
Shadow hissed and snarled as he looked at his own hands with vitriol. He wants to chop them off for what he did. His mind was still hazy from transforming into Doom Morph. He wants to fucking scream.
He should have been in better control.
He shouldn't have let his instincts go haywire.
Sonic's scent was just so…
And the way his voice was so needy…
And the way Sonic spread for him so easily…
How wet he was, how tight he was…
Shadow was going to be sick. Bile rushed to the back of his throat as his head spun.
He needs to get away. He needs to get far away. He can't speak to Sonic or his friends ever again after doing what he did. The thought of ever coming across the blue hedgehog again made his stomach churn. He can't hurt that boy anymore than he already has. He can't and he won't.
His biology was starting to lose control again as black liquid began oozing from his skin. Those cursed long tendrils shot out of his sides as if taunting him.
No. He can't risk this happening again. He doesn't know where he'll go. It just can't be anywhere near Sonic.