@WyrmSpawN  
Or at the end of the movie when they bring the magic back she gets magic wings and horn which will appear and then disappear.
 
I’m thinking they are made of magic based on the fact they are the same color, but it could still be foreshadowing their plan for Sunny in the show for her to become a new princess.

@Background Pony #1354  
Maybe it’s an accident between her two needed disguises and ponies around her go ‘it’s a miracle’.

@Background Pony #635E  

 
Why would she be disguised as an Alicorn?

What, already ? I mean it’s not going to hurt this time if they indeed do it that early  
HOWEVER  
>>2646367  
This is Pipp Petals.As you already know,she’s a pegasus and a princess to boot.Plus here she’s wearing a fake horn for reason to be determined. There’s a possibility as this was already discussed that this is a disguise

@Background Pony #9511  

 
I also think it’s a “pony up” transformation from EQ that allows Sunny to become an alicorn for a short while, maybe just with her friends. We really know very little about alicorns, only that they are among the most powerful beings when they are fully grown and in their full potential, in the magical world of Equestria / Equus. But that means that Sunny will be a permanent alicorn in the end, we can hope that it will be a long time before this, she is too resourceful as an earth pony.
 
One can only dread all the political and social earthquakes that will occur if most of the ponies learned about Alicorn Sunny - especially if the legendary and god-like alicorns had been missing for many centuries. It is with very good reasons that alicorns are as special as seen in the G4.

If it is a power-up, I love it. Even if it isn’t, I love it as well.

@Phemto  
It doesn’t look like a cosplay to me. It looks like a transformation. Just look at this horn and wings, it is like they are made of some energy.

This looks to me like it’s a cosplay. Based on the other short clips released, there’s probably a Pretty-Woman-style dressup scene where they try out different outfits, possibly as disguises.
 
Even if there’s an alicornification, aren’t we passed thinking this is Mary Sue territory? Twilight went another 7 seasons of having serious challenges after her transformation, and we saw the other alicorns get Worfed pretty regularly. I don’t really get the alicorniphobia.

Crap. Double post. Please Ignore.

Larson was playing the long game

I’m assuming she will become an alicorn at the end when she unites the tribes.

@Crunchtime  
I think it’s temporary too, maybe just like Rainbow powers in EG.

If Sunny really become a enteral alicorn at the end of movie, I will stop watching G5 show.

You gotta be kidding me! Larson worked on G5 too? XD

Holy fuck Hasbro. Didn’t you spoil alicorn Twi this same exact way? Lol.

@Background Pony #8F19  

@Background Pony #8F19  

Alicorn Sunny?…  
We’re hitting Mary Sue levels that shouldn’t even be possible!

Spoiler alert: every toy store. In the world.

The dark hand of Larson strikes again! :)

Uh oh, here we go again!

If this is in the movie, I’m going to assume it’s temporary, or a disguise, or from a dream sequence.

Sunny evolves to…

I didn’t even know that was possible!