@Phantom Rider  
I thought I just did. :)

@TheMasterEraser  
You should totally make a fanfic about this.

@Background Pony #DDCC  

 
Simple. She was being torn between her cutie mark-driven need for “Fun! Fun!” and her will to survive. In despair, she took the train to the end of the line and wandered off into the city to lose herself. There she ran into a pink unicorn who asked her what was wrong. After listening to her sad story, the pink unicorn removed the clone’s cutie mark, which disappeared in a puff of smoke because it wasn’t really hers to begin with. The artificial laughter was removed, and her mane deflated. She was a blank flank once again. Then eventually she found a new cutie mark, for dancing. But she never forgot. And one evening, her hair poofed up in a restaurant when she got close to The Original Pinkie Pie.
 
The pink unicorn, meanwhile, saw the connection between the clone’s story and her own lost childhood friend’s gaining of a mark. She wrote her ponifesto on the value of equality, gathered other ponies dissatisfied with their marks, and together they moved out to a colony town, where they could all be equal-flanks in peace.

Pacific Glow cutie mark PNG when?

THE SYSTEM IS DOWN

So we know what happened to the escaped Pinkie clone straight away!

She’s talking in hoof semaphore.

SEE THAT GIRL  
WATCH THAT SCENE  
DIGGIN’ THE DANCING QUEEN.

Molly dances every bit as awkwardly as me.

@DragonWraith  
hmmm… I can’t argue with that.  
You win this time.

@Eeveeinheat  
Yeah, it’s not very likely. It’s fun to think about it, though.
 
The one in the restaurant is all but canonically confirmed to be a surviving mirror pool clone. Sadly, we’ll probably never see her again, as she’s likely a one-time throwaway gag.

@Background Pony #0F2F  
I doubt she’s a Pinkie Clone, yeah. The one in the restaurant on the other hand…

@Background Pony #0F2F  
If she managed to escape the Ponyville Pinkie Purge, she probably has at least some level of self-restraint and poise.  
People have also put forth the theory that she’s working for S.M.I.L.E. and, as such, is under deep cover.

@DragonWraith  
She didn’t look too worried when Rarity or Pinkie showed up.  
She didn’t even like the real Pinkie’s elevator music.  
A pinkie clone would love that song.

@Background Pony #0F2F  
Remember, she’s in hiding, fearful for her life.

@Bhazor  
Then explain the different cute mark.
 
I believe they only showed that pinkie clone as a gag for when Rarity mentioned cloning herself.

@monolyth  
ALL IS ON! FEEL IT! FEEL IT! FEEL IT! FEEL IT!

@Background Pony #0F2F
 
Another pink horse, who is described as a party animal, in an episode that not only references Too Many Pinkies but includes an actual Pinkie clone.

Twerk horse best horse

Rave <3 such a qt

@Background Pony #0F2F  

Ok. Only talking headcanon here. No need for an argument.
 
I’m going with Molly is another escaped Pinkie clone. She assumed a different name and changed her cutiemark to an alternative party object.
 
The others are zoning out. She seems to keep up the dancing, but stays focused on Pinkie. It’s consistent with “Is that HER. Is the jig up? Stay cool. Just keep dancing.”
 
Also, that limbo-backbend is a classic Pinkie move.
 
Tempted to suggest we introduce an “Orphan Pink” tag for the ponies that could fit this headcanon.

@Background Pony #0F2F  
She is the third Pony who has a similar color scheme to Pinkie Pie I know. The other both are High Style (>>850903) and Surf (>>850586).

“another pink pony. it must be a pinkie pie clone rather than just another pink coated pony. hurrr”

From a distance, she really does look like Pinkie.