This is a a fan episode that /mlp/ is planning to do. It is based on a discarded concept from the show: the mane six find this pony who was raised by a herd of wild deer, and they are divided whether he should be brought to "civilization" or not.

It seems this was too ambiguous for Hasbro's tastes: what to do when both sides have a point?

And it's going to be full serious mode: no pandering, referencing, meme-tossing, cross-over, or anything like Double Rainboom.

Source?