One day, over a plate of burgers, the Doctor and Derpy became very interesting to a lecture group of 4th dimensional beings.

Note: A bunch of nonsense I've come up with after looking at the picture used as the cover art. I don't even know which reincarnation the Doctor is in this story.

Cover art is by askclockwisewhooves on Tumblr. Not sure though, I found the picture on google images in the first place.