(Be warned, cannibalism does happen, but it has an explanation, so be ready, alongside violence/death, but that's invincible in general)
"Uggggg...my head, what the hell happened last night?" I whispered under my breath, the room looking all fuzzy.
I could tell instantly that wherever I was, it was dark and had no natural lighting beyond a weird, faint green glow. Getting up slowly, I rubbed my head, looking around, and saw I was lying on a thin metallic bed with a not-so-comfy bed and pillow, with a decent blanket to go with it.
Rubbing my head, I saw I was still wearing my pajamas, or well, just some sweatpants and an old white t-shirt. I started breathing heavily, scared shitless as I began backing up into a corner, feeling something...something different about my body. I was skinnier, more muscular, and taller as well, and while I wasn't unhealthy before, I definitely didn't have a six-pack, let alone a one-pack.
Then I felt a massive migraine pounding in my head; it felt like a thousand gigantic bells were ringing all around me at once. I also felt...something vile, something old and...evil was the only word I could use to describe this sensation. I could feel something rising and falling in my chest, yet at the same time, it felt like I was chugging an entire lake's worth of water.
No, it was something worse; it was as if I was drinking the best sugary drink in existence, and yet at the same time drinking literal fire, no magma. Like the two substances were fusing to find this sort of weird balance, but that wasn't the weirdest thing so far.
No, instead I heard a computer-like voice, no, it sounded mechanical but more humanoid or like an android, whatever it was, it was now overwhelming all the other noise in my head.
[Class type chosen: Fighter]
[Good Luck in this new world of yours, Damien]
Instantly, I held onto my stomach and began puking my guts out, spewing out chunks of my dinner last night, which consisted of some old ramen I had heated up. Even then, I wasn't done yet, as I eventually reached the point where I was just puking up pure liquid like a dying, sick animal.
I did stop at some point and leaned against the wall, feeling not weak, but not at a hundred percent either, unsure of just what the hell was happening. My eyes were also starting to clear up a bit, and I could see a fully lit green shield in front of me, locking me in.
{Let...me...out.}
Then just as soon as the migraines were finally slowing down, a dark voice began whispering in the back of my mind. It felt like the same kind of vile evil my body thought I drank a minute ago, no, it was the exact same.
{LET...ME...OUT!!!!}
Instantly, I screamed out in pain, my cries echoing throughout the prison even through the closed door. Outside of it, I could hear the stomping of feet as I keeled over, feeling my body beginning to shift as fur began rapidly growing across my lower torso.
My toes began to shift around as they became more monstrous and birdlike, then my upper body began to change. It still resembled my old human torso, except it turned gray as two gigantic bat wings burst out of my back. My neck extended outward as two smaller bat wings grew from my head, and my voice became deeper...more demonic.
Fur began growing all over my body, becoming nearly pitch black as it did so, my muscles screaming in pain.
"Wh-Whats happening to me!" I screamed out as a feeling of anger and...and what I could only describe as the want to cause carnage began engulfing my mind.
Outside the cell, I saw what I could only describe as sci-fi security guards surrounding the door. They were wearing red and black suits with an American flag on the side, complete with a white visor covering their face.
"Subject 003, stand down now, you are to detransform and submit to the United States for testing now!"
My body screamed out as it launched itself forward, and dread began to fill my detached mind. My fist slammed against the green energy wall, and began tearing it apart, somehow, I mean physically tearing it apart as electricity began to fly everywhere, striking at one of the guards and launching them backward.
One that happened, all bets were off as they began firing upon me with grayish energy weapons that shot out green lasers of some kind. I could then hit my body and dissipate harmlessly off me, and that's when I felt it, I felt my lips curl up into a cruel smile.
"This is going to be so fun, I haven't slaughtered anything in quite a bit!"
"At least before my pathetic host takes back over!"
I-no my body and whoever took it over charged forward, grabbing the nearest guard by the throat, crushing it instantly, sending the others scattering through the hallway. I could feel the sick pleasure as this thing felt as he snapped the man's neck as easily as you would a twig.
I could feel the sick pleasure the demonic being felt as he charged at another human, grabbing both of his arms and tearing them off. I could hear the man scream as my body did so; the men kept on firing, though, giving the guard a swift death, hopefully, as my body turned around.
Faster than I could process, my body charged forward and began ripping the rest apart, only letting them run away for some sick pleasure I couldn't understand. Yet as the last two began running away, I could tell that whoever was running the show was planning something.
One of the guards slammed their hand against a large red button, easily an alarm button, as red lights flooded the hallway and a loud ringing began. That didn't matter to whoever was in charge, though, as they inhaled and opened up my mouth as a large source of heat began gathering in my mouth.
Instantly, a high beam of pure fire that felt as though it came from the sun itself shot out of my mouth, instantly killing the two security guards of what I was assuming was a black site government facility of some kind. Didn't matter at this point, as whatever demon was possessing me was taking pleasure in destroying this place as a large hole opened up, revealing a beautiful night sky.
"Pathetic little creatures, the fact I-*gurk*-what the hell is happening to me."
I knew exactly the reason he was saying that. I was doing everything I could to wrestle control of my body back from this monster. To try and stop the carnage I-its-no we were causing and the countless lives lost because of this thing's sick rampage.
I could feel my metaphysical hands around the thing's metaphysical throat, and wrestle for control of my body. My rage burned brighter than a thousand suns as my real body jerked around and launched itself forward out of the hole. My body jerked around as my fists slammed against the cold, hard ground, the being who possessed me starting to lose control of the body.
When I looked at our spiritual bodies, I saw my human outline, a series of dark colors like red, purple, and green, with hints of white, mostly centered around my eyes and heart for some reason. The being controlling my body was nothing but a pure-black demon-looking thing with dark-red eyes that looked like flames.
I could tell he was weak, while my-our body shifted to represent what this thing was once, but I could tell that whatever happened that fused us weakened it. Either that or whatever consituted for our soul mine was stronger than his for some reason. I used that to my advantage as I grabbed the demonic entity by the throat, forcing it down in my-our mind palace.
The whole damn thing was confusing and not what I expected after waking up in what I can only guess was again a black ops government facility. Whether that meant they actually did it to me or if some demon took control of my body and the supernatural was real, I couldn't tell yet.
I raised my right hand, baling it into a fist and began slamming it over and over into its face, sending puffs of black smoke flying.
"How...How...is a mere human...able to do this, to fight me for control of the body here of all places."
"My death... no, my battle with Lucifer is still incomplete, you damnable HUMAN!"
He then grabbed my hand with both of his hand ad began prying me off him, doing his best to overpower me. But that was the thing, here in the realm of the mind/soul, he didn't have all the power; he was strong in the physical world, but my soul was stronger.
I didn't know why, nor did I understand, but I used that to my advantage and charged forward, grabbing him by the throat with both hands. I didn't know how long I could keep hold of him, nor did I know if choking would even work in this realm. So I did the next best thing and flipped him over, tossing him away from me.
Our body thrashed about in real life as several sci-fi-looking helicopters began surrounding me in real life. They fired at me with these massive blasts of red energy that destroyed the ground around us, or me, but didn't hurt me, well, it annoyed me as I was now sure my body was running on autopilot, aka animal instincts.
It launched itself forward, grabbing the head of the helicopter and tossing it into another one, causing a huge explosion, sending a few others spiraling out of control. In all honesty, I wasn't paying attention to it as I charged forward, grabbing the black demonic being's head with both hands.
I then began headbutting him over and over, sending wisps of black smoke all over the place, probably the mind version of blood as I beat this demonic being. I didn't understand why, but with every hit and wisp of black smoke, my mouth curled up into a cruel smile.
Tossing him to the ground, I lorded over him and began punching him over and over. Taking some form of sick pleasure from this fight. Like...like I was just some mad gladiator, whose only mission was to fight over and over.
Eventually, I stopped as I saw that the only thing I was beating was but a small wisp of whoever took control of me. I felt myself heaving somehow, both my body and my mental self, as my eyes widened in horror seeing the carnage my body had caused, as he was surrounded by several half-eaten burn corpses.
Looking at the demon, I put my foot over what constituted its throat in this realm, disgust clear as day in my eyes. While it no longer had much mass to give it definition, I could tell there was nothing but anger and contempt in its eyes.
"Fine little...human, you win this day, but know this...I will return, for I am...always within, ready to take over when...you...are...weak."
With that final middle finger, the being dissipated to where who knows where.
"Yeah...fuck you too."
I said as I began to slowly regain control of my body, no longer having to wrestle for control. Still freaking out from...everything and unsure of what to do next as I began feeling my senses again, alongside...the bitter taste of burnt flesh.
Then I puked it all out, unable to stomach the idea of having eaten...eaten a person, from the burnt wreckage of some weird hi-tech helicopter I destroyed. Grabbing the sides of my head, I began screaming, my voice coming out deep and demonic sounding as I launched myself into the air.
I-I-I didn't know what to do, I just kept on screaming and flying rapidly all over, unsure of where I was going. My whole body is just swirving with no idea of where I wanted to go, my soul and body still out of synch as I began crashing back to the earth.
Wth a sudden thud, I landed at the top of a small mountain, forming a tiny crate where I curled up and...and kept on screaming. From the fact I now had the body of some demonic entity with that being still slumbering beneath my own mind, the fact that the government had kidnapped me and wanted to-to experiment on me, probably.
I kept puking the entire time, not knowing what to do as I felt my body slowly...slowly change back, my skin still greyish looking but now more humanoid.
"What the hell happened last night?" I whispered to myself, knowing no one would answer.
(adding this little tidbit, but some stuff from the CYOA is going to be adapted to better fit the world of Invincible (TV), and spoilers, it will have some stuff to do with the age lore they dropped, not immediately, but it will)