((I think I might get in on this, if you fellas don't mind. This is actually my first time filling a request, but the idea for Gamzee's shadow just lent itself so well, so I thought I might have a crack at it. I dunno if it's any good, but here it is, anyway:))
Barely aware of what he was doing, half-unconscious as ever, Gamzee Makara wandered into the largest big-top in the Land of Tents and Mirth and was met with the sight of another young troll, standing across the room with his back to him.
"HeY, bRo!" Gamzee called, waving across the room at the other troll. Who was that motherfucker, anyway? He had a lot more hair than any of the other players; and anyway, Gamzee didn't remember inviting any of his homies down to LOTAM...
The hairy motherfucker turned around slowly, and if he wasn't so baked out of his mind on sopor slime Gamzee may have taken a few steps back. Was this a motherfucking mirror, or something? Even though it was dark, Gamzee could clearly make out that this other troll looked exactly like him. Wait, no; there were differences...
Normally Gamzee would immediately chalk an occurence like this up to miracles, but there was something highly sinister about the other Gamzee standing across from him... His face was covered in cuts, and there was something about the way he was smiling that filled Gamzee with... what was this feeling? It didn't feel nice, that was for motherfuckin' sure... Fear? Is that what Karkat or the others might call it? That one where you didn't feel like smiling; you wanted to turn and run, far away from whatever was causing the unusual feeling, 'cept you couldn't 'cause your feet wouldn't move for some reason...
Oh, and of course, he was black, emitting a dark fog and his eyes were glowing. However firmly one believed in the beauty of all things, that was always a little bit offputting.
"HEEEEEEEEEEEEEEYYYY, BRO!" the Other Gamzee yelled, waving a bloodied paw at the one who'd just entered the tent. "how you doin?"
Gamzee was about to reply that he was pretty chill, actually, thanks for asking, when the other one cut him off. "NOT ALL MESSED UP IN THE MOTHERFUCKIN HEAD FROM ALL THEM THOUGHTS OF MURDERIN YOUR FRIENDS, I MOTHERFUCKIN HOPE!?"
"uH... i dOnT ThInK I FoLlOw," Gamzee said. His eyes were half-closed, but they narrowed a little further upon hearing this, and he had a vague inkling in the back of his mind that he might actually kind of follow, just a little bit.
"course not, bro. here, come have some motherfuckin pie." the Other Gamzee smiled and held up a pan of slime, cooled to perfection. "AFTER ALL, WE CAN'T HAVE YOU ALL REALIZING WHO YOU REALLY ARE, THEN GOING ON A MOTHERFUCKIN RAMPAGE AND KILLING ALL THOSE MOTHERFUCKIN "FRIENDS" OF YOURS, CAN WE!?" On the word "friends", the Other Gamzee grinned wider and bit down on his lip, drawing blood, before tossing the slime pie across the room.
Gamzee's smile wavered, and he tried to retrieve it, and he failed. "BrO, i DoN't hAvE A MoThErFuCkIn cLuE WhAt yOu jUsT SaId." This was a lie. Gamzee's mind was as sharp as if he'd been off the slime for a week, and he didn't like where this train of conversation was leading. Maybe he should just kill the motherfucker, then get back to his friends? Yeah; he could tear this motherfucker to shreds, paint the wicked pictures with his blood, satiate those urges he'd been fighting off since the day he was born...
The Other Gamzee smiled again, licking the blood from around his mouth. "yeah you do. don't lie to me, motherfucker." He stepped towards Gamzee, and Gamzee stumbled back, tripping over his feet to get away. "YOU KNOW YOU ONLY EAT THAT MOTHERFUCKIN PIE TO STAY ALL CHILLED AND SANE AND WHATNOT, WHETHER THAT'S THE WAY YOU SHOULD BE OR NOT. but it's cool. i'm chill with it." The Other Gamzee continued to walk forwards at a leisurely pace, then spontaneously lashed out, kicking over a ladder to his right and stamping on it until the rungs snapped and it collapsed into a pile of white splinters. Turning back to Gamzee and still grinning that nightmarish grin, he continued.
"LET ME MOTHERFUCKIN HELP YOU, MOTHERFUCKER. LET ME BE ALL SORTING YOUR SHIT OUT." Gamzee backed away again, and bumped into the flaps of the tent, which had sealed themselves.
"let me motherfuckin help you. let me sort your shit out," the Other Gamzee repeated. He switched back to the scary grin again, but then made a kind of strangled noise in his throat and continued, as though he thought staying in his calm persona would be beneficial for now, however hard it may be not to be switching back and forth between the two.
"here. take my hand. just accept who you really are, and then we can all be getting down to what's really important." The grin returned in full force, and Gamzee spun around and started clawing at the tent-flaps, trying desperately to get away from this motherfucking terrifying motherfucker.
"WE CAN BE ALL GETTING DOWN TO KILLING ALL THOSE OTHER MOTHERFUCKERS. ALL OF THEM."
Gamzee looked back over his shoulder, and he saw that the grinning black motherfucker was reaching a hand out, willing for him to take it.
"nO, bRoThEr! FuCk tHaT SaLtY MoThErFuCkIn sHiT! I DoN't wAnNa kIlL My fRiEnDs!"
"oh, but you do. you can pretend you don't all you want, but you do." The Other Gamzee frowned for the first time, and it was the scariest thing Gamzee had ever seen. He pulled his clubs out of his strife specibus and swung for the motherfucker, but he just casually ducked under it, then stepped forward and pressed himself against his other. "YOU CAN PRETEND ALL YOU WANT, BUT THE TRUTH HAS TO ALL BE COMING OUT EVENTUALLY. JUST LET IT FREE, BROTHER. ACCEPT IT. SHIT'S GOOD FOR YOU."
Gamzee curled up into a ball, wanting the nasty man to go away, wanting him to stop saying these awful things. "nO! It aInT TrUe! iT AiNt!" Covering his head with his hands, Gamzee cried out the only thing he had left to say to this shadowy frowning motherfucker. "yOu'Re nOt mE!"
And then the shadowy frowning motherfucker started cackling, and the mist coming from his body spread out and enveloped him, and even as the pink-and-green sickle sliced through the outer fabric of the tent and the STRONG fist came through the hole and punched into the smoke, followed by the black-and-white lance, followed by Gamzee's chill motherfucking home-bros, it was too late. The mist moved backwards into the center of the tent, expanding as it went, and when it dissapated the other Gamzee had vanished, replaced by an enormous baby-shaped monstrosity with its' face painted white, holding a bloody hatchet in one hand and a broken bottle of grape-flavoured faygo in the other.
"GAMZEE! FUCK! WHAT THE HELL HAPPENED TO YOU?" Karkat asked, turning his head to his fetal best friend and not loosening his grip on the sickle he held in each hand.
"uH, wHAT IS, tHAT THING," Tavros stuttered, keeping his gaze locked on the huge horrible clown-beast.
"D--> well, i hardly think that's of the utmost consequence," Uquius replied, springing back and forth and limbering up his neck and shoulder muscles. "D--> more to the cru% of the matter, how long do we estimate it shall take to e%terminate, and what manner of 100t can we expect from doing so?"
The baby-shaped horror smiled down at the newcomers, displaying row after row of sharp teeth. "I AM A SHADOW... THE TRUE MOTHERFUCKIN SELF..." It raised itself from a crawling to a standing position and pointed the jagged end of the faygo bottle at these new distractions. "YOU MOTHERFUCKERS ARE NO LONGER WORTHY OF BASKING IN MY MIRACLES. WELCOME TO THE DARK CARNIVAL, BITCHES!"