Please don't list this on a work's page as a trope. Examples can go on the work's YMMV tab.
Nightmare Fuel: Halloween Horror Nights
Your time has come.
While really every single aspect about Universal's Halloween Horror Nights is basically high octane nightmare fuel, there are plenty of specific examples we can describe of things that, well, stick out to us in particular when it comes to this trope.
The Director. An ax crazy snuff film director who lets his actors get only one take. He calls it a a short take.
Lady Luck's monster form. She'll turn into this whenever you lose.
The whole "Terra Cruentus" world from the 2005 event (set inside Islands of Adventure). It's a world that literally operates off of the "sacrificing" of victims, as basically everything in that world needs blood, including for the soil, harvesting, and for the creation of weapons. So naturally, the murdering of people is commonplace there.
The 2005 website fittingly describes it as "A horizon of horror you were told exists only in nightmares." and, "A world that the practical mind refuses to see, the rational mind will not accept, and the stable mind dismisses as impossible."
On a side note, we should add that really much of the 2005 website is pretty heavy nightmare fuel, with its rather disturbing descriptions of the different sections of Terra Cruentus as well as creepy music and occasional jump scares to boot. You can find an archived version of it here.
Possibly 2008's house of the year, Dead Exposure had one room that made about 75 percent of the people entering want to turn back. It involved about 20 zombie mannequins with two or three real ones. We'd also like to acknowledge this house's only lighting was from the timed flash of a "camera."
The general idea behind the Scary Tales houses. Normally, you would associate fairy tales with innocence and safety. Not here. In these houses, they've been twisted and corrupted beyond belief.
The third Scary Tales house more so. The first two were basically just tongue-in-cheek Disney parodies set inside some wacky funhouse, but with Scary Tales 3, that's where things got truly dark and disturbing.
For people obsessed with hygiene, the bathroom scene in the Psycho Scareapy houses.
The 1999 house Psycho: Through the Mind of Norman Bates had this particularly unsettling scene that featured hundreds of eyes staring right at you.
A scene where a screaming victim is having their spine ripped out has been used in several houses for good reason.
Terror Mines involved groups of people going into a near-pitch black environment with all sorts of terrifying creatures lurking about. The only source of light was from a miner hat that was given to one person per group.
It's worthy of note that there was a house that was so unspeakably scary that the higher-ups actually pulled it at the last minute, fearing potential guest controversies. It was known as Severe Fear and was originally planned to be at the 2003 event. For most of the house, you would have been all by yourself, and the scareactors would've been allowed to touch you as well as blindfold you. Read all about ithere.
JP Extinction. Jurassic Park going haywire with the electric fences glitching out with huge sparks, Velociraptors roaming freely and popping out of the dense foliage, gruesome mutant half-human half-dino hybrids lurking through, and terrified JP scientists futilely trying to hide from all the insanity.
If you truly want to be scarred for life, take a look at some of the concept art and masks for this zone right here.And here.
The Island Under Siege zone qualifies as well. Here, all of the Marvel super heroes have either been killed in battle or given up and fled. Super villains roam the streets with no opposing force to stop them, and the remaining police force has apparently been zombified. All this happens while the villain Carnage stands proudly atop a building, announcing his final victory against all good as the city falls into chaos.
The mutated people in 2003's Toxic City and 2009's Containment.
The Path of the Wicked depicted the Wicked Witch of the West conquering all of Oz, and all the usual Wizard of Oz characters heavily twisted. A Not-So Cowardly Lion, a (literally) Ax-Crazy Tin Man, creepy munchkins, flying monkeys swooping down, and so on.
Then there was also Asylum in Wonderland, which, while actually a bit more playful than the typical scarezone, still managed to feel like a giant acid trip from hell, with its disorienting lighting and creepy background noises.
For 2006, they had a show called The Arrival, which featured each of the four HHN icons at the time being brought back to wreak havoc. Each icon would kill a person in particularly gruesome way.
The Director repeated the "electrocution in the bathtub" stunt from the aforementioned 2003 commercial, but this time with a girl as the victim.
Jack the Clown had a man placed in a giant blender...and then proceeded to turn it on...
The Storyteller, with her scissors, goes in and brutally cuts a man's tongue out.
The Caretaker performed one of his "living breathing autopsies", happily ripping the victim's organs out one-by-one while he screams in agony, until he finally rips the victim's heart out.
2007's Carnival of Carnage, while a bit more comedic, had several examples of this as well. The storyline of the show was that Jack had "selected" several people to be in his carnival show, and knowing the nature of the event, you can probably imagine what happens to them before we actually tell you in detail.
Each victim is killed in a certain way, such as one being slowly shoved into a wood chipper, another chainsawed to death, while another had their head literally bashed to pieces by a sledgehammer.
Even a security officer attempting to intervene got placed on the classic rack device, which subsequently rips his torso in half, causing his intestines and blood to splatter out everywhere.
Queue Line Videos
The one for Screamhouse shows a wide range of disturbing imagery mixed with unsettling police reports.
The Cold Blind Terror queue video is extreme nightmare fuel. It combines some of the most horrifying and gruesome clips from movies like Day of the Dead and The Ring and adds on a disorienting effect to the clips combined with disturbing sounds. Viewer discretion is heavily advised.
The Demon Cantina queue video, especially the really unsettling sound of revving engines at the beginning and end of it. You may never look at (or hear) motorcycles the same way again.
Special mention also goes to the queue video for The Skool. One of the scariest pieces of music you'll ever hear combined with clips from The Children of the Corn. Yeah, good luck with sleeping.
In the Screamhouse: Resurrection queue video the Caretaker and his minions are shown literally ripping a young man apart internally and happily partying around with his organs. All while he's still alive. And you can assume there's no anesthesia involved here.