With a name like ''ComicBook/{{Hellblazer}}'', this trope would seem to come naturally...

Spoilers below:

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* In the very first issue, John Constantine drops by to visit his friend Gary "Gaz" Lester. Letting himself in, he finds that the place has an awful stench and hasn't been cleaned in weeks. The syringe he finds with tiny bug carcasses suspended in fluid is disturbing, but when he enters the bathroom and finds Gaz sitting in the bathtub complaining: "[[http://dc.wikia.com/wiki/Gary_Lester_(New_Earth) ... it feels like there's bugs all over me]]", it's pure NightmareFuel. What's causing Gaz's problems is even worse: he's become the host of a famine demon who causes people to literally consume the objects of their desire, i.e. start gobbling up money or jewelry as if it's the last, most delicious food on earth [[note]]See the liquor store scene in the film version for a similar premise[[/note]]. One disturbing panel shows a bodybuilder [[ITasteDelicious chewing on his own muscular arm]]. The only way to keep innocent bystanders safe is for Constantine to seal Gaz alive in a wall.
* There's also ''Rare Cuts'', a compilation of the most Nightmare Fuel-o-riffic ''Hellblazer'' short stories, which culminates with John and a friend trying to save a village from a mind-warping pagan festival with [[UncannyValley masks]] involved. Those big, hideous, over-the-whole-head ones. And guess who's the only survivor.
* The ''Son of Man'' arc? Back when John was still in Ravenscar, he got sprung (unwillingly) by a psychopathic mob boss who demanded John resurrect his dead boy, and John was too loopy to think of a way out except for conning his friends into helping him summon a demon into the child's body. Which he left there, to do whatever it wanted for the next twelve years. And then the story gets really nasty.
** Also the flashback when he's begging to be allowed back into Ravenscar, even though they torture him on a nightly basis in there.
* ''The Horrorist'', where John has stopped even caring about the awful things he sees.
* In ''Hard Time'', what he does to the prison.
* ''Highwater'', guest-starring some of the crowd from ''Preacher.'' [[{{Expy}} (Not really, but they might as well be.)]]
* More recently, the ''Scab'' storyline, where John is addicted to putting on a monster's skin.
* The Newcastle Incident itself. It's not what happened that's so bad (we've seen worse since), but what's haunting about it is that it all happened because of recklessness and ignorance.
* [[JohnFKennedy The man with the hole in his head]], from ''Damnation's Flame''. '''[[AndIMustScream Dear God...]]'''