* CrossesTheLineTwice: In-universe example: [[CombatPragmatist Luna's reaction]] to Harry [[spoiler:using the Elements of Harmony to supercharge a fire spell]]? Laughter to the point of tears.
* DuelingShows: With Fanfic/MyLittleDenarians.
* FridgeHorror: [[spoiler: Obsidian never was reincarnated in the story, meaning the Order Triune had been trying to kill an innocent man for nothing. The Order Triune has supposedly wiped out Obsidian before, but since he never resurrected, how many innocent ponies could the Order have killed before?]]
** At least one event that is infamous for leading to many many ponies dying [[spoiler: is definitely due to The Order trying to kill a pony they thought was Obsidian. It couldn't have been him, as he was sealed about 1200 years ago, but there is mention while talking about his returns early on of one event 700 years ago. And the Order's attempt to kill that particular "Obsidian" lead to the pony version of the Titanic disaster.]]
* HarsherInHindsight: You know, come season 3, Twilight's the one who, in-canon, if she and the other ponies were human, has broken the Laws of Magic (specifically the prohibitions against mind control, as per ''Lesson Zero'', time travel, as per ''It's About Time'', transforming others, as per ''The Cutie Mark Chronicles'', and arguably, killing people, as per ''Too Many Pinkie Pies''). At least by ''Magic Duel'', Trixie's now a repeated Second Law breaker.
** The passage in Chapter 10 of ''False Masks'' where Harry talks about what it looks like when a father loses his child is kind of hard to read in light of ''Changes''.
** Episode 5 of season 3 ''Magic Duel'' features the Great and Powerful Trixie using a dark source of power, that corrupts her to get revenge on Twilight Sparkle. Pretty much the concept of ''Strange Friends'' sans Dresden.
** When Harry sees Twilight's library, he says he can totally imagine it going up in flames. [[Recap/MyLittlePonyFriendshipIsMagicS4E26TwilightsKingdomPart2 He wasn't wrong about that.]]
** ''False Masks'' has its own funny aneurysm moments: that comment Michael makes at the beginning of the story about being called to drive Harry to wherever? [[spoiler:That's probably where he first saw Obsidian.]] Bob noting how empty the Nevernever is on the Way to Equestria? [[spoiler:The corpse dragon that ultimately kills Novel Notion is likely responsible... [[AttackOfTheFiftyFootWhatever AND IT'S HUGE.]]]]
* HilariousInHindsight:
** The one off 'Extra stuff' of Maggie writing her own fan-fic where Harry marries Twilight and then takes her to live in Equestria with them got a whole lot more plausible come ''Literature/SkinGame'' when it's revealed Maggie really is a fan of the show.
** In the [[Recap/MyLittlePonyFriendshipIsMagicS5E9SliceOfLife 100th episode of FiM]], it's revealed that Bon Bon [[spoiler: is an agent of a top-secret anti-monster agency, which Lyra had no idea about]]. It fits startlingly well with what happened with them in ''False Masks''.
* MoralEventHorizon: Harry sees the foalnapping of [[spoiler:Spike]] as this. It makes him so angry he almost kills the defenseless kidnapper. [[UnstoppableRage And when the Mane Six try saving him from himself, he turns on them.]]
** [[spoiler: Novel Notion's extermination of the entire Order Triune to summon a demon. The fact that they all were demented zealots who more or less brought it upon themselves does not weaken the horror of the act.]]
* NightmareFuel: Harry being [[spoiler:possessed by the Nightmare]] in ''Strange Friends.''
** When Harry realizes [[NothingIsScarier he hasn't a clue how or where his attackers are going to attack ''from'']] in ''False Masks.''
** We finally learn why the Order Triune is so deadset on destroying anything even remotely resembling Obsidian in ''False Masks'' chapter 14. [[spoiler:Obsidian's corpse after his first death disintegrated anypony who touched it as well as anyone who came in contact with the black vapor surrounding it. He then resurrected himself 50 years later and tried to take over Equestria AGAIN.]]
** [[spoiler:Novel Notion/Bookmark sacrificing nearly the entire Order Triune to summon a Demon. Even the heroes are horrified.]]
** [[spoiler:The real Obsidian being powerful enough to give two Knights of the Cross, a veteran Warden, and the ''Gatekeeper'' a run for their money before apparently being permanently slain by Michael gives Harry the chills.]]
** [[spoiler:Novel Notion and the Counsel of Thirty's final end. [[LaserGuidedKarma Yes, it is EXACTLY]] [[KarmicDeath what he deserves.]] [[HoistByHisOwnPetard Yes, he has no one to blame but himself.]] But it's still hard not to have a stab of pity for someone who is SwallowedWhole by [[AttackOfTheFiftyFootWhatever a demon whose head alone is the size of a house]] and then ''[[CruelAndUnusualDeath slowly dissolves to death inside their devourer's stomach acid.]]'']]
* OneSceneWonder: [[spoiler:Doctor Whooves' second cameo in chapter 20 of ''False Masks'', where he gives Harry a pep talk and reminds him just how hard the mane six would take his death if he ran off after Novel Notion on his own.]]