From Rarity! She fights giant crabs.
No, I mean the origin of the Meme. I never saw her fight a crab once in the cartoon show or the comic books. -_-'
Oh no, it totally happened. Rarity and Fluffle when on a quest to find the best sea-shells for a water-theme dress. And Fluffle fell in love with spelunking and accidentally awakened the Crab King, Crustacious. What followed was an epic battle too amazing and breath-taking to be put down in mere words.
Linky plz? I wanna see it. 
this will explain everything
[link]
[link]
I had a feeling.
The feeling was correct.
The feeling was correct.
*Claps* I knew the video wouldn't have anything to do with giant crabs but I didn't think of that.
Sir or madame, I curse thee to suffer one million paper cuts and then be thrown onto a lake of lemon juice that is surrounded by mountains of salt that are covered in a way that you must crawl through to get out. The paths through the salt mountains will be filled with perfume room gauntlets.
Aww you got me! 
Yay! It's been a long time since I've seen someone do that. ^_^