This is based on opinion. Please don't list it on a work's trope example list.
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Nightmare Fuel in GaoGaiGar.
- Lord Pasder, leader of the Machine Kings and their Zonder minions, the entity known to the Gutsy Geoid Guard as "Extra Intelligence-01", is a nightmarish Mechanical Abomination that looks like a cross between a giant mechanical heart and a human face, with red, bulbous eyes and a grimacing mouth. The way his whole body constantly squirms and pulsates, combined with his deep and menacing voice, makes him come off as truly freaky and unsettling.
- Speaking of the Machine Kings, let's talk about Penchinon. The other Machine Kings have relatively human forms, with the most cybernetic-looking being Polonaise, whose head looks like a cross between a steam train and a mechanical caterpillar. All of them can also assume a perfectly normal looking human form. Then there's Penchinon, whose default form is basically a tugboat with a single mechanical eye, legs, and pincer-clawed hands. His "human" form, on the other hand, looks like a Monster Clown wearing an old-timey sailor suit, with his right eye missing and covered by a patch emblazoned with an anchor symbol, a too-wide red-lipped toothy grin, and a staring mad yellow eye contrasting a half-purple, half-white face. It says a lot about Penchinon's state of mind that this is his idea of A Form You Are Comfortable With.
- What truly makes Penchinon terrifying is his laugh. A high-pitched, reverberating "BREEEEEE!" in the Japanese, and an instant, staccato cackle in the English.
- Episode 20 has an infamous scene where the vice-principal of Mamoru's school opens a door in the toilet and finds Penchinon in there, sitting on the toilet and laughing at him. Why is he there? Because he felt like being creepy.
- In episode 3, the government decides to [send a full assault squad and helicopter to "retrieve" little Mamoru, after the kid transformed and purified another monster. They have at least five guys yank the kid, thrashing and crying for his parents, off of his feet. All while saying that they didn't want to hurt him.]
- Also the previews for episode 31. A satellite drifting quietly in space, a close-up of a small rock beside it... spooky music? And then BOOM! FULL-SCREEN PASDER, complete with his Evil Laugh and Pagliaccio DEVOURING HIM WHOLE. And just to top it all off? Episode 31's title: Farewell, GGG.
- Episode 16: A university festival vanishes into a fireball, with little warning, leaving nothing but a massive crater. What would give small children nightmares is the way the attack is presented - it's very reminiscent of Sarah Connor's dream sequence in Terminator 2: Judgment Day and unlike any other so far, we see the injured and the scale of the disaster, implying that people actually died this time.
- Guy's BRUTAL Beatdown of the Zonuda. Sure, it seems awesome, but when you hear Guy's anguished and enraged screams as he destroys the beast that contains Mikoto by ripping it apart, even after GaoGaiGar starts falling apart, you can't help but shiver. He doesn't even resort to using any of his special attacks, just roaring in rage and tearing it limb from limb. And when it comes to the core... he just rips it out, no Hell and Heaven nor Goldion Hammer.
- FINAL invokes this by the boatload, but special mention has to be given to episode 2 :
- Mamoru (actually a replicant, but the color scheme and Mamoru using his powers makes it EXTREMELY hard to tell) goes and manipulates or outright kills everyone in his way to acquire Q-Parts, with blatant disregard for life or decency, pulling at heartstrings and gas-lighting his friends with lines such as "Believe me! The whole universe is in danger! Why won't you understand?", "If you won't listen to reason, you leave me no choice!", "I'm not wrong, YOU are!", while refusing to actually give any explanation, to stall for time before pulling a sucker punch. The whole thing would leave most people feeling downright nauseous.
- And then it is revealed that Mamoru's replicant has been twisted into THAT by Palparepa's Mind Control.
- The fight between "Mamoru" in GaoGaiGar (based on a deathly white Galeon, which immediately raises a lot of questions) versus Guy in GaoFighGar. Some of the expressions Mamoru wears are downright inhumane, and Guy himself is reduced to barking orders for the Goldion Hammer (even Goldymarg is very much nonplussed at the idea of being used against Mamoru), and to finish, Berserker Tears as he finally resolves to go beyond the Godzilla Threshold and use Hell and Heaven, after seeing Mamoru destroy ChoRyuJin. That Mamoru might have been a replicant, but what Guy did in that fight was 100% on him and he was clearly NOT okay at all with having had to go that far.
- Not to say anything of the damage to the city both super mechanoids are fighting in, which Guy lampshades as Mamoru winds up a Rocket Punch. The fight entirely plays straight how a battle between mechs of that size should go down, mercilessly unleashing for maximum effect all of the Destructive Saviour horror that the series had averted until now thanks to the GGG crew's competence and precautions (using the Dividing Driver to create a safe battlefield, evacuating civilians, etc...)
- FINAL episode 5 :
- We get an absolutely horrifying flashback of Renais going through Cold-Blooded Torture to coerce her into loyalty to BioNet. Her backstory as a whole is this too, what with being abducted and having her mother killed.
- Just as the good guys have a Hope Spot after freeing J and J-Ark, Palus Abel reveals what the Sol Masters have in store: the replicants of GGG super mechanoids, brainwashed and uttering the Madness Mantra of "Destroy. Destroy. Destroy.", and for good measure a Brainwashed and Crazy Guy piloting replica-GaoFighGar, who also follows the Madness Mantra before going in full Screaming Warrior mode, prepped to use the Goldion Hammer. Not only is the Oh, Crap! factor utterly horrifying, but this is nothing compared to Guy's face while under the Mind Control, and the anguished scream of Mikoto.
- The good guys also get a preview of what it feels to be on the receiving end of the Goldion Hammer. It is so horrific it breaks the Mind Control on the repli-Mobile Corps, who we get to see disintegrated into light screaming. Awesome Heroic Sacrifice? Yes, sure, but still very nightmarish.
