Sally-Anne Perks is sorted before Harry as in canon; in reference to this fic, she is described as "a pale waifish girl who looked oddly ethereal - like she might mysteriously disappear the moment you stopped looking at her, and never be seen again or even remembered." Sure enough, she makes no further appearances.
“Trying to navigate the halls of Hogwarts was like... probably not quite as bad as wandering around inside an M.C. Escher painting, that was the sort of thing you said for rhetorical effect…" “A short time later, Harry was thinking that in fact an Escher painting would have both pluses and minuses compared to Hogwarts.”
Many of the phrases which the painting of the elderly lady says to Harry are drawn from the Cheshire Cat.
One of the notes written to Harry by the Game Controller is a reference to The Hitchhiker's Guide to the Galaxy: "Ten out of ten for style, but minus several million for good thinking."
In reference to this fanfic, Harry says "And if someone bumps into me the Time-Turner will not break and will not trap the whole castle of Hogwarts in an endlessly repeating loop of Thursdays."
The cube saying "blorple, blorple, blorple" in Dumbledore's office is a reference to the Infocom text-adventure game "Spellbreaker."
McGonagall discusses the recent disastrous employments of two Defense professors, Professor Blake (who was caught with THREE fifteen-year-olds in a broom closet) and Professor Summers (who failed to teach material correct in the Harry Potter universe).
One evil individual mentioned in passing is named Mornelithe Falconsbane, a reference to the dark wizard who is the main villain of Mercedes Lackey's Mage Winds trilogy.
Quirrell mentions a list he made that is suspiciously similar to the Evil Overlord List.
In a demonstration of a martial arts fight, one of the combatants tries to sweep the other's leg.
We learn that mindflayers were exterminated by Harold Shea. This matches with the original making allusions with historical wizards.
Both The Tragedy of Light and Gargoyles appear to be children's stories in the Wizarding World, the latter of which is meant to teach young Slytherins about a cunning businessman (unnamed, but assumed to be Xanatos).
Several of the irresponsible and dangerous acts of Harry from the original books are pointed out
A sixth-year Gryffindor student casts a curse at a sixth-year Slytherin student, not knwoing what it does, only knowing it is to be used against one's enemies.
Harry himself uses "don't brew high-level potions without supervision in a bathroom" as an example. In the original books he brew polyjuice just like that.
Mr. Bester is the Legilimens hired to train Harry. Harry creates an alternate persona in his mind to try to foil Bester's Legilimency; this persona is Kimball Kinnison of the Lensman series.
An offhand comment is made about a girl (Tonks) who can magically turn her hair bright red (not orange, red) who, upon splashing her tea on herself, briefly became a black-haired boy.
The comment about Bill thinking he was an old man who'd gone back in time to 'fix things' is a joke about Peggy Sue fanfics.
A reference to the Ministry passing a marriage law is likely a reference to the Marriage Law challenge which has spawned a whole category of Hermione/Snape fanfiction. It generally involves the Ministry banning pureblood marriages, to improve the gene pool, and allowing purebloods to force muggleborns into marriage arrangements. This one, however, proposes to ban all marriages, mirroring the reaction of several people when they first hear of the concept.
Chapter 39:
Dumbledore taps his fingers through a black plate inscribed with the word "Leliel," a reference to the 12th Angel from Neon Genesis Evangelion.
Chapter 43:
We learn that Harry plans to become an Animagus so he can turn into a peregrine falcon
Harry gives Hermione a letter that contains the answer to a mysterious question sealed with wax inscribed with the number 42.
Chapter 47:
A reference to the founders of Hogwarts fighting Lord Foul.
Harry extinguishes his light with the word dulak; the typical word for extinguishing light is nox, Harry instead used the word the Raistlin Majere used to darken the Staff of Magius in the Dragonlance series.
Mr. Avery — maybe; Avery actually is the name of a Death Eater in canon (which could be a shout-out by J. K. Rowling, or not — it's a reasonably common English surname).
The Montagues — Montague is likewise the name of one of the Slytherin quidditch players in canon, so if it's a shout-out, it's more likely attributable to J. K. Rowling than to Eliezer Yudkowsky.
The kinds of aliens Harry suggests to Draco that humanity might eventually encounter resemble two species that humans run into in EY's novella Three Worlds Collide.
So my version of the thought, Draco, is that when we go out into the stars, we might find other people there. And if so, they certainly won't look like we do. There might be things out there that are grown from crystal, or big pulsating blobs...
In the Quirrell's list of rules, rule thirty-four is "Become Animagus", i.e., learn to turn into a snake. This is another shout-out to the Evil Overlord List, there rule thirty-four is an inversion of this: "I will not turn into a snake. It never helps."
Quotes the first two lines of Tom Lehrer's song "Be Prepared," a callback to Harry quoting the song to explain why he needs to be Crazy-Prepared to McGonagall in Chapter 6 (see also Second Verse Curse below).
"I am going to be in Ravenclaw. And if you really think that I'm planning to do something dangerous, then, with respect, you don't understand me at all. I don't like danger, it is scary. I am being prudent. I am being cautious. I am preparing for unforeseen contingencies. Like my parents used to sing to me: "Be prepared! That's the Boy Scout's marching song! Be prepared! As through life you march along! Don't be nervous, don't be flustered, don't be scared — be prepared!" (Harry's parents had in fact only ever sung him those particular lines of that Tom Lehrer song, and Harry was blissfully unaware of the rest.)
Harry's password includes the Marx brothers' "Swordfish," "friend" from the Lord of the Rings, and "melon" (well, "mellon"), the Elvish word for "friend."
Mary's Room, where Harry and Professor Quirrell have been having lunch, is in Mary's Place, owned by "Jake," which suggests that the "huge genial Irishman" whose entrance allows Harry to slip out the door unnoticed is probably Mike Callahan. Also an unintentional reference to the thought experiment "Mary's room."
"We're the Grey Knights of Chaos," said Neville's voice.
Hermione intends to emulate Superman. It doesn't work as planned.
Daphne Greengrass and Neville Longbottom basically summon lightsabers. They deflect spells.
And finally she grasped her wand in both hands and shrieked, "''Lucis Gladius''!"
she slashed out with her blade of light like it was a Beater's bat, and hit the stunbolt back at Harry who just barely managed to twist out of the way.
Daphne's title Greengrass of... Frolicking Woodland Creatures is allusion to Happy Tree Friendsnote possibly a Recursive Translation of the German version of the show's title, "Fröhliche Baumfreunde" and Sparkly Unicorn Princess is to, well, sparkly unicorn princesses. "Sparklypoo" is a reference to a famous fan comic in which this fifth house of Hogwarts existed to hold all of the over-the-top Mary Sue fan characters.
Later edited to replace Miles with Lupe Cazaril. Yudkowsky says that this is because Miles Vorkosigan is already attending Hogwarts.note And because apparently some people complained about Sci-Fi references in a fantasy novel. Which makes one wonder if they even read the previous 69 chapters.
Harry wrote the above chant to imply the ritual sacrifice of the Outer God, Yog-Sothoth.
During the 'ritual,' Tracey and the girls are protected by an AT-Field.
for the short moment before the bolts struck and vanished upon a dark red octagon that appeared in the air around the girls, and then disappeared a moment later.
Professor Quirrell refers to a ritual that uses two of the components of the Seething Death wizardry from The Legends of Ethshar, and also shares another unfortunate characteristic with that uncontrollable weapon of mass destruction:
"Even so, the most terrible ritual known to me demands only a rope which has hanged a man and a sword which has slain a woman; and that for a ritual which promised to summon Death itself - though what is truly meant by that I do not know and do not care to discover, since it was also said that the counterspell to dismiss Death had been lost."
Harry yells "Tunafish!" before triggering the flashbombs the Chaos Army had created using the energy stored in acorns. This is drawn from Nick Pollota's "Bureau 13" novels, in which the protagonists, a team of troubleshooters belonging to a secret government agency created to counter paranormal threats, use the same signal when they set off the flashbombs in their wristwatches. This becomes such a signature move for them that they refer to themselves in the later books as 'Team Tunafish'.
Chapter 79:
Quirrell claims to have been in Fuyuki City, Japan in 1983.
Harry quotes Tom Smith and his Incredible Bread Machine "The rule of law, in complex times, has proved itself deficient; we much prefer the rule of men, it's vastly more efficient..."
Chapter 81:
People falsely believe that Merlin "fought the dread Totoro and imprisoned the Ree."
In their duel, Mad-Eye Moody wordlessly fires seventeen Sagitta Magica to take down one of Harry's cloaked Time-Turned selves.
While we're at it, Moody mentions that he once tracked down a young Japanese man who attempted to fool him with shadow replicas.
In the same chapter, Moody mentions using the Killing Curse on one Gerald Grice, whose victims included a girl named Blair Roche. His descriptions on how one has to "want" the curse to work are highly reminiscent of Rorschach's mental breakdown and his subsequent murder of Grice.
There is also a character called Mad Drongo in this chapter, although he goes by Adrian Turnipseed.
Quirrell is suspected to be a man called David Monroe, an inspiring figure throughout the last war. But he's not Less Wrong's OC; the character shares a name and reputation with one from nonjon's fic A Black Comedy. This David Monroe turns out to be a Tom Riddle created when the Diary horcrux ate Neville Longbottom; Quirrell/Monroe is Voldemort in disguise, after coming back from Albania. Perhaps the Diary was there in the Methods-verse? Both Monroes are at one point called 'the next Albus Dumbledore', too.
Chapter 87:
Harry: "Sir Gareth, owner of a transportation company that won the 19th-century invokedshipping wars... monopoly on oh-tee-threes... I see."
Harry: "I wonder if there's an official name for that in the literature? Like the 'turned up to eleven effect', maybe?"
Chapter 88:
The title of this two-chapter sequence may refer to the second book of Spider Robinson's Death Killer Trilogy, a seminal work of transhumanist/immortalist science fiction.
Lunch in the Great Hall of Hogwarts on April 16, 1992 consists of breen and Roopo balls, the latter of which were also served at Mary's Place in chapter 26. Both items, in Babylon 5, were noted as being indistinguishable from Swedish meatballs, of which every culture with whose cuisine G'Kar was familiar had a version.
Chapter 89:
The Weasley Twins need to use fire spells in order to fight the troll which has got in. One uses the canon Incendio; the other uses Fuego.
When Harry is persuading Neville not to feel guilty for Hermione's death, he inverts the lesson of Kakashi's bell test:
Harry: It's true that in this chaotic world, soldiers who can only follow rules and regulations are worthless. However, soldiers who follow rules for the sake of protecting their friends are -
Later on, Quirrell makes a very small reference to stories in which wizards have attempted to resurrect the dead. Among others, he mentions the Elric brothers, the drama of Precia Testarossa, and Akemi Homura.
Chapter 98 references The Two Towers.
Draco: "I return to you now, at the turn of the -" ([tide] in case you wondered.)
"D-do-do you know what you're saying?" Daphne's voice broke. If Lucius Malfoy heard his heir saying that - he'd skin Draco and turn him into trousers!
Draco Malfoy smiled, metallic robes gleaming in the light of his full corporeal Patronus; it was a smile both arrogant and dangerous, like being turned into a pair of leather pants was beneath his concerns.
Chapter 100:
The Parisian and Buchholz Hydras are real, as mathematical games at least. They do take an unimaginably long (but finite) amount of time to kill.
Tracey: "…and everyone knows what happens when there's a girl and a werewolf and a vampire all at the same time!"
This is after Tracey has already declared she was "too young for such things" among many other innocent comments, presumably in reference to Fifty Shades of Grey.
The unicorns we see are:
Alicorn, whose avatar◊ was introduced as a reward for a piece of fanart◊. There is a quip referring to how all the other fan artists got their real names in the story.
Hagrid: What'd you have called 'er? Hannah, or some such?
"An alicorn's a unicorn's horn," Hagrid said, now louder. "Don't know where yeh all started thinking it meant a unicorn with wings, 'ere's no such thing I ever heard."
Chapter 105 has Quirrell mention that the the Philosopher's Stone can perform human Transfiguration; another nod to Fullmetal Alchemist and its version.
The "golden pathway" that Harry sees stretching into the future is reminiscent of Leto Atreides II's political agenda, whose purpose also was to ensure the survival of humanity, and was also dubbed a Golden Path.
In chapter 120, Narcissa feels like she has spent a decade in cryonic suspension.
She'd felt frozen, stopped in time…
The spell Minerva uses on her, 'Eunoe', is a reference to the titular river in Dante's Comedia. The river Lethe is said to cleanse one's memories, whereas Eunoe is said to restore one's positive memories.
Harry's phrasing when talking to Hermione about whether or not they'll ultimately fall in love evokes Baz Luhrmann's song "Everybody's Free (To Wear Sunscreen)," and it's noted that he isn't wearing sunscreen.