"It's official, definitely havin' nightmares tonight!"
—Jaden Yuki
Just because it's a Lighter and Softer Affectionate Parody of the original series doesn't mean Yu-Gi-Oh! GX is any worse at bringing the scares.
As with all Nightmare Fuel subpages, spoilers are unmarked.
- Trueman and Nightshroud's (the one from the last arc) monsters could qualify. Along with Trueman and Nightshroud themselves of course...
- Dark Archetype is a revolting creature just next-door to Relinquished in terms of weird. The Dark Psycho Eye Trueman summons during his duel with Axel using it is also pretty bad...since just when Axel destroys that monster, it opens up an enormous eye in its chest, which is the trigger for Trueman to Mind Rape Axel throughout their duel.
- Trueman himself is a Humanoid Abomination, whose body seems to be made out of cards...cards that are constantly coated in darkness, signifying that they've fallen victim to the negative effects of the World of Darkness. Most of the cards in his deck? Those are more than likely the very cards corrupted by negative emotions, and since the World of Darkness' influence is getting stronger, that just gives Trueman more and more cards to work with, making him harder and harder to defeat. Also doesn't help that he eventually starts appearing in more than one body and starts dragging people into the World of Darkness, as a show of his increasing power.
- Darkness Bramble, which bursts through Nightshroud's chest, Darkness Outsider, which is a clown which opens its face to spear things with its brain tentacles and bring them over to its master's field, and Darkness Neosphere especially.
- Nightshroud himself, perhaps one of the most visceral villains next to the original series' Zorc. He appears as a massive goat-headed skeleton with five wings to serve as his duel disk, and the way his cards manifest is always in a flash of darkness deliberately inverting the normal flash of golden light signifying that a card is played, which helps cement him as the Eldritch Abomination that he is ...which is solidified when we get his personality. Unlike the Card-Carrying Villain nature of his predecessor Zorc and the later Don Thousand, the Well-Intentioned Extremist that was Z-ONE, and even the Omnicidal Maniac known as Z-ARC, Nightshroud is disturbing in that he's less a person than a force of nature, demonstrated all the more by his own card being a field spell rather than a monster. A world of negativity that's both sentient and actively antagonistic to humanity, who believes that his Assimilation Plot is a 100% natural course of action and to be expected after all of the prior arcs created enough dimensional disturbances for him to appear. He's always calm when speaking to Jaden (minus his ranting and speeches about this philosophy, but even then, his echoing voice lends those a creepy vibe), and fully believes that humanity will fall into despair after he's defeated and that he will return. Why does he believe this? Well... the following scenes reveal that he is correct in some way, concerning each of the three series coming after...
- One of these scenes is a charming sight of a destroyed Duel Academy that he claims is the future of the world. While dismissed at the time, later series reveal that no, this was the future of the world, to some degree. That ruined future? Very similar to the world after the Meklord Emperor Genocide in 5D's, aka the Sequel Series to GX. Nightshroud knew about it.
- Another scene has him describe the universe as having started from a card, which in ZEXAL is revealed to not be a metaphor, it is quite literally true: The Numeron Code was a powerful card that played a role in the creation of the universe. While ZEXAL's relation to 5D's continuity-wise is unknown, it does in fact, take place after GX. Meaning that Nightshroud knew about a powerful artifact that only ancient inter-dimensional aliens should have had knowledge of.
- Finally, his modus operandi, taking advantage of blackened bonds of the duelists and their spirit cards, and his claiming that the negative duelists would bring themselves to ruin? He's right again, as Zarc would fall victim to a similar phenomenon, with the audience demanding more and more violent duels in his era, triggering the creation of Supreme King Dragon Z-ARC.
- All of the above gives Nightshroud this feeling of omnipresence, that he is always there, that his influence continues to persist. His claims that he will always come back? Those may very well be fully vindicated if he truly knew about all of these catastrophes, which continues to increase the scope and dread that he brings about. Even though Jaden defeated him, there's a very good chance that yes, he will return one day, and his claims that he'll succeed amidst Jaden believing that other duelists will ensure that he never resurrects might have more weight to them.
- The World of Darkness. An alternate dimension where people experience their worst fears, doubts and regrets until they cannot take it any more and give up their individuality willingly. For example, Alexis fears she would not be a good teacher, so she stops trying and gives up her dream. Thank God Jaden is able to snap her and everyone else out of it and free them all.
- How they get there is unpleasant to begin with. They get cornered by Trueman, who, through a combination of words and beating them in a duel, with the occasional Mind Rape, sends them into that awful dimension.
- His duel against Axel is a candidate for the most disturbing in the franchise. Taking the form of Axel's father, Trueman proceeds to torment him by bringing up an incident from his childhood where his parents got caught up in a car crash and he could only save one in time. While it's eventually revealed that Axel's father regained consciousness in time to save his mother too, Axel has never forgiven himself for cynically choosing to save his father because Axel felt that he was the one who could best take care of him, something Trueman mercilessly exploits to screw with Axel's head and bait him into making a fatal mistake at the last moment. Cue Trueman's trap card and Axel's loss, as the flames of their monsters and the flames in Axel's memory of the burning car blend together as one. Worse, you can see a horrified Axel realise said mistake just a second too late, in a perfect example of how badly you can slip up under psychological warfare.
- Even the normally immune Hassleberry falls after Trueman, disguised as Sorano, shows him a vision of his past life as a dinosaur gruesomely devouring another, whose bone would be integrated into Hassleberry's body in the present day.
- The above situations are just two of the cases where the victims fought back. Tsutumo, who is one of the first victims of the World of Darkness, is just a young child infuriated that he can't win, which summons Trueman into his room. Who then looms over the young boy menacingly before dragging him into the World of Darkness and assuming his form, which he then uses to do the same to almost everyone in Domino City except for Seto Kaiba.
- How they get there is unpleasant to begin with. They get cornered by Trueman, who, through a combination of words and beating them in a duel, with the occasional Mind Rape, sends them into that awful dimension.
- The Facial expressions pulled by Sartorius when The Light of Destruction fully possesses him are worthy of rivalling Yami Marik's facial distortions.
- Yubel. Just, Yubel. A batshit insane stalker that considers love to be sharing of all feelings, most notably pain. Judai is stalked by a monster that is not only possessive to the point where they try to kill anybody else that gets close to him, but genuinely considers making his life a living hell a sign of love. The fact that they looks like Yami Marik and Yami Bakura's love child doesn't do anything to lower the nightmare factor.
- That living hell consists of breaking him down mentally from the shadows until his mind literally splits by making him believe Jesse is dead, turning his friends against him and making him believe he murdered them, all to trigger his Superpowered Evil Side who then goes on a genocidal rampage.
- What they do to Jesse and his family is pretty horrifying. The show doesn't go into much detail but what little we get is bad enough. They corrupt the Crystal Beasts and Rainbow Dragon into evil imitations of themselves - implied to be fully conscious too - and then rip Jesse's soul out of his body to imprison him in a prison of anguish, in their own words. They then use his body to hurt Jaden as much as possible, punish the Crystal Beasts for daring to speak with Jaden, and even try to trick Jaden into thinking Jesse has turned evil all because Jesse dared be important to Jaden. Imagine just getting close to someone and then an insane stalker decides to torture you and your family for it.
- There's something inherently disturbing about seeing Jaden, the happy-go-lucky protagonist, losing everything before turning evil.
- Episode 45 and 46 give us the lovely image of Banner's mummified corpse. Have fun with that. Oh, and his homunculus body has this nasty habit of cracking and falling apart alive too.
- Episode 65. Every single element of the Underground itself is incredibly disturbing to begin with (Electric Torture as entertainment for masked spectators, cage matches, the implication that duelists have died after losing there, etc). We watch Zane, who is already in the middle of a mental crisis, be mocked and tortured until his mind snaps and he obliterates Mad Dog in a brutal rage. Mad Dog gets blasted right through the steel bars of the cage and just lies there, immobile and smoking. He might be dead. He's unconscious and horribly injured at the very least. Zane's terrifying Slasher Smile at the end when he's back in the Pro League ends the episode on one hell of a nightmarish, ominous note. A little more Fridge Horror about how bad the Electric Torture must be in the Underground: this character, who barely made any sound when hit directly with a 4000-point attack in a shadow game, is screaming in agony after a loss of only a few hundred Life Points.
- Titan's fate in Episode 6 is pretty hard stuff, even in the 4Kids dub. After faking a Shadow Game, somehow a real one gets started and he becomes possessed by a spirit in the abandoned dorm that forces him to continue the match even though he's terrified and likely would have abandoned his contract with Crowler to escape the situation otherwise. When he loses he's dragged in the Darkness (The Shadow Realm in the dub) by a swarm of tiny blob monsters, and in the dub his last words are crying out to Jaden to tell his kids he loves them. He's one of the series' villains who most certainly did not deserve it, especially with the dub giving him an implied backstory of an ex-carny who turned his special effects knowledge into a career as an illusionist "hitman" to support his family.
- Titan however returns as the 6th Seven Stars and he becomes far more sadistic than he was before as in Alexis's duel against him he clearly enjoyed tormenting her both physically and mentally, even openly says that seeing her in pain brings him joy as a shadow duelist.
- The Jinzo spirit in episode 14 has a terrifying voice. Not to mention his deck is filled with creepy monsters. The reason why Jinzo is there, three students tried a ritual to summon duel spirits, and for some reason they tried to summon Jinzo. Well it worked all right but Jinzo demanded three souls. He already got two of the three students and whenever the third tried to escape the academy, there was Jinzo on the boat waiting for him.
- Episode 38. Not supernatural or anything, but the sea captain is just downright creepy, no matter whether you watch the original or the dub.
- Adrian, in the later parts of his arc, does some majorly disturbing things. Watching Echo insist on sacrificing herself for him and him accepting so easily is horrifying.
- Because the dub didn't air season 4, where things got better, the English series seems to end with Jaden leaving Earth forever, still in the midst of an emotional breakdown.
- Episode 98: Destiny HERO - Plasma and everything about it. Not only are the monster itself and its effect disturbing to look at, but The D has been using it to trap human souls, including Aster's father. It's actually worse in the dub, where Aster's father just disappeared and Aster only finds out now that this is what became of him.
- Doll Chimera takes the Creepy Doll trope and cranks it up to eleven. It starts out as a decrepit mannequin that stands on all fours like a giant spider, and each time it's destroyed, it comes back and grows additional torsos and limbs with its own effect. At full power, it has three torsos joined at the hip, each with its own limbs and head, and the inherent Freudian imagery just makes it worse.
- Everything about the Duel Ghouls. They're cannon-fodder Mooks and fairly easily defeated, to be sure. But not one single ghoul stays down when it's defeated, and they swarm. You either duel them 'till you drop and become one of them, or you run and pray you can get far enough away. There are no alternatives. One poor unnamed kid decides to attempt to hold the Smart Ball, and just run past the ghouls without responding to any challenges. Can't be turned if you're not willing to play the game, right? Wrong. They swarm him, corner him, converge... and he rises again as a newly-minted ghoul, no duel necessary.
- Being a vampiress Camula thrives off of this! While her backstory makes her somewhat sympathetic she's still an evil vampire who with every duel won, steals a soul she plans to use to resurrect a member of her vampire race. The faces she makes during her duels do not help!
- Add to that, her signature card Illusion Gate requires the cost of someone's soul if she should lose the duel. Not her soul or even her opponent's, anyone she chooses, a tactic she uses against Zane with Syrus’ soul and nearly does against Jaden with the souls of everyone present. Thank goodness for the Shadow charm from Atticus!
- Mr. Stein. Think about it: All kids have that one teacher, whom they don't really pay attention to in class, as the subject does not interest them or the teacher simply lacks the skills. Normally kids can at least count on teachers to not take their potential anger about this on them. Not with Mr. Stein though. He is actively out to stop and hurt Jaden, despite knowing that the Biobands could put him jeopardy, and later also Alexis, as he agrees to let Viper drown her, for blowing off his class to go shopping with her friends. His backstory might explain his actions a bit, but he is still in a position of power and endangers Jaden, Alexis and all of the other kids by actively siding with Viper. Even without all the supernatural threats and the water-filled pit in Alexis case, he is a walking cautionary tale for teachers, who let their personal emotions affect their treatment of the students, which is supposed to be unbiased and certainly not threatening...
