Most Esoteric Jokes in the Show

[Ganondox 899]

Despite being a kid's show, Friendship is Magic has some very esoteric jokes. Here are three that I know of: 

1. Deceptive Cadance - explained here.

 

2. The Amniomorphic Spell - it's a complicated way of saying Starswirl the Bearded is a Hairy Potter. Apparently this one wasn't intentional, while the previous one was, but it's still good: https://scifi.stackexchange.com/questions/123139/why-did-starswirl-the-bearded-invent-an-amniomorphic-spell

3. Time Dilation Equations - from the episode It's About Time: https://derpibooru.org/406579?q=english

Does anyone know of any more? Anything that's more obscure that just a reference to a popular film geared at adults works (so the Big Lebowski and Rick and Morty cameos don't), it's got to be truly esoteric. 

[Once In A Blue Moon 895]

It wasn't in the show itself, but the Tails of Equestria RPG core book's introductory story has the Mane 6 planning an expedition, with Twilight proposing using Dijkstra's algorithm to find the shortest route.

I'm not sure that it's 'truly esoteric', but I did also notice that Commander Hurricane and Captain Spitfire both share names with Second World War fighters. Lightning was also the name of a fighter jet (several, actually), but that was probably just a coincidence (although if Tornado turns up then I may revise that.)

Edited April 14, 2019 by Once In A Blue Moon

[Ganondox 899]

12 hours ago, Once In A Blue Moon said:

It wasn't in the show itself, but the Tails of Equestria RPG core book's introductory story has the Mane 6 planning an expedition, with Twilight proposing using Dijkstra's algorithm to find the shortest route.

I'm not sure that it's 'truly esoteric', but I did also notice that Commander Hurricane and Captain Spitfire both share names with Second World War fighters. Lightning was also the name of a fighter jet (several, actually), but that was probably just a coincidence (although if Tornado turns up then I may revise that.)

I’d count it - most people aren’t knowledgeable about WWII fighters.