After gathering all the Pinkies at town hall, Twilight announces the Pinkies must do something only the real Pinkie Pie KNOWS how to do, that way the clones would not know what the real Pinkie is capable off. So each begin doing different feats, none the real Pinkie would do.
 
Finally, Pinkie snaps out of her depression, and bounds over to an idling clone, opens her mouth wide, and eats the clone. Fluttershy, Applejack, and Rainbow Dash all blush at the sight, being in either the situation of the clone, or Pinkie, whilst Rarity and Twilight look on in disgust.
 
After being convinced, Twilight then shoots the remaining clones back to the Mirror Pool. Recovered from eating the clone, Pinkie shouts out to Twilight; “Ah, come on Twilight! I could have gotten them all!”