@MorphinBrony  
I have a feeling that if more of the scene were used, I would of guessed it was a reference to something.
 
Either way, my mistake.

@Technature  
That was a JonTron reference.
 
Here, have the original clip.

@MorphinBrony  
………yyyyeeeeeeeeeeeeeesssssssssssssssss??????????????

@Technature  
Ever heard of JonTron?

@MorphinBrony
 
When someone gets annoyed that Pinkie Pie, who has shown this sort of behavior since literally the second episode of the series, starts singing out of nowhere.
 

@MorphinBrony  
More like was never invented in this entire universe. But yeah, that’s Pinkie for you. Random is her middle name. Pinkie Random Pie.

WHAT THE FUCKING FUUUUUUUCK.
 
There was no hint of this episode being a musical. And now all of a sudden Pinkie Pie… Pinkie Pie here comes and she starts RAPPING… rapping hip-hop… rapping in a style of music that won’t be invented for another 110 years after this scene ends.

@Technature  
Hasbro/Hub - the ones that pick the previews - has been very good this year to pick segments that give the flavor of the story but without giving away the big jokes. No MMC-type “oh, here’s 6 and a half minutes of a 22 minute show” previews.
 
This clip (the rap), is arguably the first S4 clip that really gave away much, but yet it’s also a prime clip for promotion (“Rap? on My Little Pony? This I have to see!”) compared to much of the rest of the episode. Of course, if you want maximum enjoyment and surprise, avoiding any of these clips is still good.

@RIG
 
This is why I don’t watch previews anymore.
 
I knew nothing about this and it probably made it even funnier. It came so far out of left field that I couldn’t stop laughing and had to watch the episode later to catch what I missed.

@Lawful Girly  
Straight outta Canterlot  
Crazy motherbucker named Sparkle  
From the gang called ponies with attitude

@Albus Fahrenheits  
NWNeigh?

@Lawful Girly  
Ponies with Attitude?

@Bhazor  
The Notorious PIE.

Run p.i.e?
 
Pinkie Plav surely?

But the animation looks cool.

I don’t really like rap…

“What now!?”

It could’ve been better, I think.

Pinkie, stop.

The way her hooves move is so cute!

Can you make a gif of the part where she dances like Snoop Dogg?

lol  
So white! :P

@TheAntiCat  
my work here is done

I am really terrified right now…

@CranberryRodent  
4Chansayitsoitsfunny,4Chansayitsoitsfunny,4Chansayitsoitsfunny,4Chansayitsoitsfunny,4Chansayitsoitsfunny,4Chansayitsoitsfunny