On the subject of "Cupcakes" (which sounds pretty horrifying, if your reactions are anything to go by), do not. Under any circumstances, ever. Ever. Watch the remix of Pinkie Pie's "Smile" song. Just don't. Trust me. I got ~30 seconds in, thinking it was a harmless animation.
I have never been so wrong in my life.
I should have listened to Pinkie's advice from "Cutie Map" -- that smile was just too big to be real.
It started off with a disclaimer: this song may cause extreme joy, rated M for Magnificent, and all that. True that, thought I. Then it cut to a semi-realistic animation. Not bad, thought I. Then the unmentionable happened.
Sweet Celestia! thought I. Do a brony a favor and pass the brain bleach! (I actually mentioned this a while ago on the bad day board: I felt legit sick afterward.
Moral of the story: pony grimdark: bad.
This had been a PSA from an emotionally scarred teenager.