Insanity: My Immortal Enemy

So, about the previous chapter.

The reason why I did not include the Cupcakes Killer, or Pinkamena Diane Pie, is I personally believe Pinkie Pie would use her insanity to protect her friends, rather than violently mutilate them.

But the plot of this chapter derives from the Changelings. Or, rather, the Forestling. So here's the deal. The Forestlings were hit by the brunt of the love wave in the wedding, overloading their senses with it. They were therefore unable to consume love. They feared love, and as a result consumed the emotion of fear.

Late at night, a Forestling replaces Pinkie Pie after viewing one of her nightmares. Then, it takes on her persona of insanity and awkwardly attempts at being a happy cheerful pony in the day.

That is why Peyton notices a change after some time.

Anyway, context out of the way. See ya next chapter!