You were expecting Queen Chrysalis.
 
BUT IT WAS ME, COZY!

@Amethyst_Crystal
 
This isn’t up for debate. Why would Chrysalis not gloat about vengeance when she thinks she’s absolutely alone with Starlight, and declare herself an “Empress” instead of a “Queen”?
 
Also, you just know the writers would’ve revealed her to be Chrysalis before throwing Cozy Glow in Tartarus if they actually had that in mind, and it would also heavily undermine the moral that a regular pony, even a child, is capable of great evil.
 
As it is, there isn’t a shred of evidence to support this theory, and unless they decide to throw in a plot twist with zero foreshadowing, it’ll stay that way.

@Background Pony #5035  
She didn’t steal it, Rarity gave it to her. But she did steal her idea.

I like the idea that ‘be a sweet little filly named Cozy Glow’  
is one of multiple revenge schemes Chrysalis is attempting,  
and perhaps the one she ends up dedicating the most effort towards.
 
Otherwise, Cozy is either some kind of demon,  
or the writers are really following through with  
‘irredeemably evil child’ character in a family cartoon,  
which boggles the mind.

I think she’s chrysalis.

@Wildcard71
 
I disagree. I think that Suri Polomare is the one that belongs in Tartarus for stealing Rarity’s one of a kind fabric.

@Background Pony #5035  
No doubt: Cozy is worse.
 
@EwaZor  
No!

Starlight dies in the finale lol

@GryphonStar5678
 
They did air the episodes in order, just long before the United States.
 
@AC97
 
We already have a pony like the one described in your first spoiler tag. Suri Polomare.

okay

Is this bait? Who could be this much out of the loop?

It was an idea I thought a bit while watching it, but I’m personally glad it wasn’t confirmed.

This kind of thing is the reason why the US airing purists is hillarious.

Are we still doing this?

@Wildcard71
 
(S8 Finale spoilers, in case you haven’t actually seen it yet)
 

 
Because Neighsay was actually a red herring, and had no idea who Cozy Glow was before the finale.

@ArtColter  
Then there remains the question why Neighsay and Cozy Glow duel for the headmaster job.

@GryphonStar5678
 
I know for a fact at least some people on this site haven’t seen all of it yet. Why would anyone be subscribed to the spoiler-free S8 thread otherwise?
 
If being courteous stops just one person from being spoiled, why not do so? Better safe than sorry.
 
(Also, I’ve seen mods edit spoiler tags onto comments)

@AC97  
Spoiler really has lost its purpose this season with Nick and Boomerang giving no care at all about airing in proper order. I pretty sure nearly everpony has seen the entire season, just waiting for the rest to give up on hiding away.

(Remember to mark spoilers here guys)

Wow, somepony is behind. I haven’t even watched the finale yet either because of being too busy but even I already know the answer from just minor looks online.

Cozy Glow is not Chrysalis. Cozy Glow is a plant by Chancellor Neighsay (perhaps his niece), there to get close to Princess Twilight and stir the pot among the Student Six. The former has been shown numerous times, delivering mail to Twilight in “Friendship University” and volunteering to help in the library in “What Lies Beneath”. The latter is mostly apparent in that same episode, where she points out to the students how and why friendship is not in their nature.
 
Further evidence:  

No, she isn’t. There’s nothing you could say that isn’t a stretch considering how they act completely different around Starlight, especially since Cozy’s debut was one episode before.
 
The entire point of Cozy Glow was showing how a regular pony could be capable of great evil, and how not everyone who seems to be your friend is actually your friend.
 
It’s not up for debate in my eyes. The fact that the finale didn’t throw out so much as a hint as to this being the case doesn’t help either.

The finale is already out, boi.