Josh Haber has officially revealed that Ed Valentine is the writer behind the upcoming "Cart Before the Ponies". So far he has two writing credits on Friendship is Magic from way back in the earlier seasons, with Three's a Crowd and Flight to the Finish.
Expect it this weekend!
And in other news, apparently Mike Vogel was the one that came up with the idea for it.
Thanks to Toxic Mario for the heads up.
