->'''Harry Potter:''' I'm scared, professor.\\
'''Professor Lupin:''' Well, I'd consider you a fool if you ''weren't.''
-->-- ''Film/HarryPotterAndThePrisonerOfAzkaban.''

''Literature/HarryPotter''... it's just a series of books about a boy going to wizard school, right? Totally kid friendly, right? [[TemptingFate It's late]], [[SchmuckBait but give it a read anyway...]]

Spoilers abound. You have been warned.
%% Please avoid self-inserts, however interesting: "I fell out of my chair when I read this" isn't actually an example. "This troper" counts as a self-insert.
%% Avoid natter. This isn't a forum.
!!Novels (and films) with their own pages
* ''Nightmarefuel/HarryPotterAndThePhilosophersStone''
* ''NightmareFuel/HarryPotterAndTheChamberOfSecrets''
* ''NightmareFuel/HarryPotterAndThePrisonerOfAzkaban''
* ''NightmareFuel/HarryPotterAndTheGobletOfFire''
* ''NightmareFuel/HarryPotterAndTheOrderOfThePhoenix''
* ''NightmareFuel/HarryPotterAndTheHalfBloodPrince''
* ''NightmareFuel/HarryPotterAndTheDeathlyHallows''
* ''NightmareFuel/FantasticBeastsAndWhereToFindThem''

* "The Warlock's Hairy Heart". A wizard decides he's above the weakness of love, and performs some sort of magic to prevent him from ever loving anyone. He tries to woo a woman to be his trophy wife, but she refuses to marry him unless he shows her that he has a heart. During a feast at his castle, he takes her down to the dungeon to show here where he keeps his ACTUAL, STILL BEATING HEART encased in a crystal casket - a heart which, thanks to lack of love is now twisted and hairy beyond recognition. The witch understandably freaks out and begs him to put the heart back in, so he cuts open his chest and puts it back in. The witch then embraces him. Time for a HappyEnding with the wizard saved by ThePowerOfLove, right? Wrong. The warlock's heart is so completely unused to feeling love that it has deteriorated to an animalistic state, driving the wizard to find a true heart. He does this by ''cutting out the witch's heart and trying to magic out his own.'' The dinner guest then find him downstairs ''both hearts in his hands with him licking the witch's heart.'' [[LiteraryAgentHypothesis In the liner notes]], Dumbledore even points out that many wizard parents won't tell it to their children "until they're in an age where they won't have nightmares".

!! Pottermore stories

* From the story of the founding of the Ilvermorny school of witchcraft and wizardry.
** The protagonist Isolt comes across a family of wizards that was being attacked by a hidebehind, a monster that preys on human-like creatures. While people preying monsters aren't anything to bat an eye at as a dangerous encounter in the potterverse, the circumstance of the attack can be quite chilling. The main reason it got the jump on them is that they were on a trip and the father mistook it for a boggart. Imagine the scenario: you and your family want to go somewhere new and fun, so you go to a different continent for your trip. While there, you encounter something that is scary at worst, and is easily gotten rid of. You try what you think will work on a creature you think you have identified, [[OhCrap but it doesn't work. The creature isn't what you thought it was]], and it attacks. Isolt and William arrive too late to save the parents, which are ''[[ThereIsNoKillLikeOverkill about to be disembowled by the monster]] near their severely injured children'', and if it wasn't for Isolt and William, their kids wouldn't have survived the encounter. [[AdultFear How many more wizard families - or even muggle families have gone on vacations to other countries, and met similar fates due to a simple misidentification of a creature they thought was mostly harmless?.]]
** When Chadwick Boot sees the sillouette of his evil step-aunt Gormlaith Gaunt sneaking towards his family's home at night after waking up from the warning sound his wand made.
-->" - Chadwick’s dreams had been haunted by the figure of an old witch creeping through the trees towards Ilvermorny. Now he saw his nightmare made true."