History Fridge / HarryPotterAndThePrisonerOfAzkaban

* The scene where Sirius and Lupin interrogate Pettigrew and give him a TheReasonYouSuckSpeech starts out as well-deserved but gets scary after the two openly admit to planning to kill Pettigrew, especially when we have every reason to believe that they would have done it, had Harry not intervened (admittedly, just to have Pettigrew submitted to a FateWorseThanDeath in Azkaban and probably to clear Sirius' name by showing everyone the very person Sirius was supposed to have killed. This is hammered home by the Ministry of Magic song "Marauder's Map".) The casual way they discuss killing Pettigrew is very disturbing as well as the fact that they had no problem trying to do it in front of Harry, Ron and Hermione. Sure, he may had deserved it but that doesn't change the fact that three kids would've had to see two adults (one of whom they'd considered a mass murderer a while ago and the other, a respected and trusted teacher) murder someone in cold blood. Plus there's no guarantee that producing Pettigrew's body would've cleared Sirius's name since as Pettigrew mentioned, the officials could claim that Pettigrew had chosen to hide himself from Voldemort spy and mass-murderer Sirius

* Harry's dad was the genius behind the three Animagi - an incredibly difficult transfiguration to pull off which he pulled off as a teen (as did Rita Skeeter). Back in ''Philosopher's Stone'', Ollivander described James Potter's wand as "good for transfiguration". Wand and wizard were more than just good; they were exceptional. Exceptional enough that with James' and Sirius' help, mediocre Peter, whom [=McGonagall=] was often harsh with, managed to pull it off by 4th or 5th year.

** There's also the fact that she takes academia more seriously than Harry or Ron. They're fine with having an easy class where they can just make up answers for homework, but Hermione wants to actually be academically challenged by a teacher who knows their material (and, while Trelawney does have a fair amount of talent, it's clear that she's not nearly as good as she makes herself out to be).

* In this book, Lupin mentions a particularly horrifying bit of information about Dementors, that if you are around one of them for too long it will feed on you until you are reduced to "...Something like itself, soulless and evil". If Lupin's words are correct, and being fed on by the Dementors has a risk of essentially draining away your better nature until you become much more evil and practically soulless, then this fits nicely with one way [[spoiler: Barty Crouch Jr. can be interpreted. Someone who may ''not'' have been evil, or at least not as bad as they were when they went in, twisted and drained of all but the worst of who they were, and left a shell of what they once were, which would explain Barty Junior's traits of UndyingLoyalty and his obsession with Voldemort, as well as his cruel and manipulative behavior, and his rejection of Winky's love or his mother's sacrifice. If he was a better person before Azkaban, with issues but other positive qualities or doubts about his devotion to Voldemort, then they and everything else that made him a more "complete" person might very well have been literally sucked out of him by the Dementors!]] Overlaps with Fridge Horror.

* Also, imagine how Lupin must have felt after reading an entire set of essays (including one written by his best friend's son) about, essentially, how to kill werewolves--in other words, how to kill ''him.'' Not to mention the fact that he's very lucky the only person in the entire class who put two and two together is Hermione, despite Snape dropping a giant hint.

* In the film, Lupin turns on some music during the lesson with the Boggart. As the students will be confronting a creature that manifests as their worst fear, the music is an attempt to keep the mood light and give them a better chance of casting the spell.

** Peter Pettigrew became a rat, suspicious and parasitic animals that steal food and spread disease. Also, to "rat on" someone is to betray them by informing the authorities of a crime or misdeed they committed.

* Fans make much of Remus being the only werewolf to attend Hogwarts, with bashing fics claiming Dumbledore admitted him to groom him into becoming his pet werewolf for the Order. But a more thorough look at the events as Rowling presents them leads to an unpleasant conclusion: Remus’ admission to Hogwarts was a pilot program — one that failed thanks to the Marauders, especially Sirius. In the era before Wolfsbane Potion, Remus had to go to the Shrieking Shack every time he transformed. While he was in school, his friends discovered his secret and became Animagi to keep him company. During this time, they let him out of the Shack and into the Forbidden Forest. It is unlikely Dumbledore was aware of these escapades, but the last straw came when Sirius lured Snape to a face-to-face encounter with a transformed Remus. This drive home to Dumbledore the hard truth that it was not feasible to admit werewolves to Hogwarts, because the student body at large lacked the maturity to handle things responsibly, and it would only be a matter of time before a student was turned or killed. Even with Wolfsbane Potion, it would only be a matter of time before an idiotic bully decided it would be fun to sabotage or swap out the potion.

* Fans make much of Remus being the only werewolf to attend Hogwarts, with bashing fics claiming Dumbledore admitted him to groom him into becoming his pet werewolf for the Order. But a more thorough look at the events as Rowling presents them leads to an unpleasant conclusion: Remus’ admission to Hogwarts was a pilot program — one that failed thanks to the Marauders, especially Sirius. In the era before Wolfsbane, Remus had to go to the Shrieking Shack every time he transformed. While he was in school, his friends discovered his secret and became Animagi to keep him company. During this time, they let him out of the Shack and into the Forbidden Forest. It is unlikely Dumbledore was aware of these escapades, but the last straw came when Sirius lured Snape to a face-to-face encounter with a transformed Remus. This drive home to Dumbledore the hard truth that it was not feasible to admit werewolves to Hogwarts, because the student body at large lacked the maturity to handle things responsibly, and it would only be a matter of time before a student was turned or killed.

* Sirius Black's nickname, Padfoot, seems a pun like the rest of the Marauders, because dogs have padded feet. But after looking into the mythology of the British Isles, the black dog is a death avatar that goes by many different names, one of which is Padfoot. This gives more credence to Trelawney's prediction. Sirius is a death avatar; his friends from school all die rather violent deaths, as does Sirius himself, Harry and his cousin Tonks.

* When Harry, Hermione, Ron, Neville, and Ginny are confronted by the Dementor on the Hogwarts Express, Harry passes out because, as Lupin later states to him: "There are horrors in your past that others don't have." Of the other four kids, the one most affected is Ginny, "who was huddled in her corner looking nearly as bad as Harry felt". Not much emphasis is put on this because she's only ''two months'' removed from having been MindRaped by Diary Horcrux-Voldemort. Lastly, Neville was very pale and had a higher voice than normal, which foreshadows the reveal of his parents having been tortured into insanity by Crouch Jr. and the Lestranges, and no longer recognising him.

** His worst fear isn't any of the violence from the first war happening again. Instead, his worst fear is of transforming into something that can do much worse to the people he cares about. He's more afraid of being the one hurting his friends than of them being hurt by someone else--and sadly, without the threat of war hanging over them (at this point), he's the most realistic threat to the people around him.
* When a desperate Death Eater blew up the street, the cover story was that it was a gas explosion. But what if Muggles at the gas works got MisBlamed for it?

* In Harry's Divination lesson, Trelawney predicts that Harry was born around Midwinter. Only, he was born on 31 July. Midwinter could have been referring to at or around the winter solstice. The winter solstice is 22 December, far from Harry's birthday, but nearer the birthday of Tom Riddle (which is New Year’s Eve). Trelawney wasn't reading Harry's mind, [[spoiler:but the piece of Voldemort's soul within him.]]

* In Harry's Divination lesson, Trelawney predicts that Harry was born around Midwinter. Only, he was born on July 31st. Midwinter could have been referring to at or around the winter solstice. The winter solstice is the 22nd of December, far from Harry's birthday, but nearer the birthday of Tom Riddle. Trelawney wasn't reading Harry's mind, [[spoiler:but the piece of Voldemort's soul within him.]]

* Professor [=McGonagall=] is kind to Harry on learning that Professor Trelawney predicted that he would die due to having the Grim in his teacup. She reassures him that the lady makes those predictions every year, and jokes that while Harry still has to do homework, he doesn't have to turn it in if he dies for real, cheering him up. Then again, Harry has nearly died twice -- both times to Voldemort-- so that plus the threat of Sirius Black has made Minerva consider that Harry might be a little more worried than an ordinary student that doesn't have a mass-murdering wizard trying to kill him. He notes it's not like [=McGonagall=] to make such quips, and she was already worried about him given the Dementors made him faint. 
* Similarly, Ron gets mad at Hermione for dismissing the Grim, saying that it's a real phenomenon for wizards. He saw Harry nearly die last year, if not for Lockhart's rubble stopping him from helping with the basilisk or the magical car saving them from the Acromantulas. Ron may not express it much, but he does worry about Harry's safety. 
* In one of the greatest doses of irony, the black dog that Harry sees while running away from the Dursleys is ''not'' the Grim; Sirius reveals that it was him, going to check on his godson before the latter would leave for Hogwarts. Harry before this hadn't known Sirius's name or what he looked like, let alone the backstory of why the man would "want to kill [him]". If Harry hadn't summoned the Knight Bus by accident, Sirius could have transformed and given his side of the story long before the rest of the Wizarding World did, maybe even warn Harry about Ron's rat and helping him find a place to stay for the night. In fact, several fanfics like ''The Dogfather'' went this route.