- The_None's Giygas. Put simply, if you once feared but then grew desensitized towards Giygas, this version of him will rekindle that fear, permanently. He can summon stuff like headcrabs, as well as employ his endless repertoire of PSI-powers, at seizure-inducing levels and plays horrible sound clips of agonized wailing and screaming at completely random intervals. One of his special moves involve throwing the victim into one of two stage fatalities from EternalChampions: Challenge From The Dark Side (they function like quick time events to make it easier), and they are signaled by a red flash picture of Spengbab. When a new round starts, it looks as if you're fighting someone completely different, like Youmu, but SPENGBAB IT'S A TRAP. And when he wins...he'll either flash Gorny stuff at you, a Michael Jackson pic that GOES MAD and...Smile.JPG.
- But Wait, There's More! Other deathtraps of his involve shooting monsters while trying to avoid shooting Slenderman...and another is the closet scene from Ao Oni. His other winposes can remind people of bizarre childhood nightmares; such winposes include a hideous face approaching the screen while appearing and disappearing randomly, bizarre lines of text in an unknown code, a computer shutdown advisory, a dark, empty hallway, another hallway culminating in a faceless man jumping you, "THE DAWN IS YOUR ENEMY", three gory death screens from Waxworks, a still of the parking lot from Portal, eventually having a giant thing crawling towards the camera, and...this.
- An obvious example would be Andres Borghi's original creations. In particular is Noroko, the Stringy-Haired Ghost Girl. She has an instant killing desperation that is a literal screamer, and a win pose where she attempts to "escape" from MUGEN.
- StormEX's Ichigo becomes this when he Turns Red.
- Dee Bee Kaw, while normally very humorous, is actually rather disquieting when he wins via the Shun Goku Hamusuta Satsu, because he stands over his opponent's lifeless body and starts laughing maniacally while the screen goes from black to red.
- Jinmen from Devilman is just as creepy as he is in his source material. He's a giant humanoid turtle whose shell is composed of the sorrowful faces of his victims. He has a super where he drags an opponent into a murky pool of water, where he restrains and attacks it while helpless. He can also trick an opponent into killing one of the faces, which bloodily explodes and causes damage. He even has a finishing move where he eats the opponent and adds its face to his collection.
- Crazy Catastrophe's 11P can be seen as this. It offers seven 'levels' of full screen stuff happening all over, with low-pitched voices from Mizuchi and Orochi, later joined by female laughter and voices usually found within Oni-Miko... the fourth and seventh levels even has the screen alternate colors between red, green, blue and white, while some of the kanji include 'Metsu' (destruction) and 'Satsu' (Murder).
- Dark Donald and Dark Excellent Donald have actual screamers coded into them upon starting the second round, first by deceiving the player by fighting (or controlling) a different character, followed by a scary picture with the loud scream like the Exorcist girl from the Scary Maze Game or Smile.JPG after which the battle resumes as normal.
- DRAGON-TIER CHEAPIES. Not only are they the strongest type of characters to ever exist, but they can also literally destroy your game and your computer!! There is a supposedly confirmed one named "Mathrus", appearing as a Felhound... and it apparently does destroy your computer. Thankfully, none of them are public for download, and very likely never will be.
- Kyouki (not to be confused by the unrelated porn-character Kyouko). Everything about Kyouki. An emaciated, towering monstrosity with a mask-like face, black sockets for eyes (except in its win-pose), and matted black hair. When you KO it, it disintegrates into a swarm of possessed-looking baby dolls, followed by a cutscene of it getting closer and closer to the screen, ending in a static image of its mask-face. It then reappears, with YOU KO'd instead as it does its disturbing win-pose.
- A tamer example, but one of Lonnir's Punisher's specials has him run over opponent with his vehicle, take them inside said vehicle, and then starts to rip them apart with his gloved hands, complete with gory sound effects.
- Felix the Cat is normally not all that bad. Just as innocent and fun as he has always been. However, in the version that comes with Brergrsart's VHFSMACVUSMRRM fullgame/compilation, he will gorily tear off his own face when KO'd, just like he did in the infamous russian bootleg of his game. Joel's reaction is the same as it was back then.
- Nijikaku is an incredibly bizarre Japanese MUGEN fullgame based off of 2chan and its various memes. While most of the game is fairly tame despite its oddness, the game has some very grotesque, violent and downright disturbing imagery as well. Examples of this include Gurocure, a team-based character that can make its opponent slowly fade away into nothing with some of the creepiest piano music ever and can also feed them to a monster made out of what is presumably flesh, Sattin, a parody of Tsukihime's Satsuki that uses a jump scare in one of its supers, then crushes its opponent, and Manamana, who has a super where she (spoilers for incredibly disturbing content) HAMMERS NAILS INTO HER OPPONENTS PENIS, ON-SCREEN. And this is only scratching the surface of some of the more disturbing parts of the game.
Nightmare Fuel / M.U.G.E.N