Fluttershy singing: “abcdefghijklmnopqrstuvwxyz, it’s the most remarkable word I ever seen. abcdefghijklmnopqrstuvwxyz, I wish I knew exactly what it means. It’s start the kind of any word as everyone can see, but somewhere in the middle it gets awfully QR to me. abcdefghijklmnopqrstuvwxyz, if I can find out what this word could mean. I’ll be the smartest mare the world has ever seen.”
 
Big bird: “Uh, actually, Fluttershy, that’s not kind of word, you can spell the letters in the book, like A is for apple and B is for banana.”  
Fluttershy realize: “Oh, of course. I haven’t thought of that.”  
Twilight Sparkle: “Perhaps Fluttershy must learn the words in every way.”  
Bert: “Well, Twilight, as long as you and your friends can spell words and count numbers at the same time, right Ernie?”  
Ernie: “Right, Bert. I will make sure to bring my rubber ducky with me to meet the ponies.”  
Oscar the grouch: “Oh, come on! Why you always bring things like that?”  
Grover: “I guess it’s taking all day to have fun in Sesame Street.”  
Rarity: “I’m glad we get alone each other.”

Also, isn’t Applejack just a bit too dark?

I wonder what Oscar did that caused RD to confront him.

Is Oscar… flipping Dash off?

Lol  
Cookie Monster’s Eating Applejack’s Hat

This needs to exist.
 
Oh Jeebus the nostalgia…

This would be the single greatest crossover in history.

Dashie, what are you doing? You leave that grumpy grouch alone, you’re just playing into his hand.

AJ: What in tarnation?! Mah hat ain’t no cookie!
 
CM: omnomnom
 
AJ: ಠ_ಠ

I don’t remember watching much Sesame Street when I was younger. I feel like I missed out on something. :(