A Day in the Life of Equestria volume 2 chapter 6

Chapter 6 is the sixth chapter of My Little Pony: The Manga's second volume. The chapter stars as she discovers the true cause of the time loop in which she has been trapped.

Story
finds herself in a strange futuristic corridor, and attempts to explore in search of Star Dancer and/or the alternate Dr. Hooves. After succeeding only in bumping into herself from three minutes in the future, she eventually comes across Star Dancer and tackles her in her excitement. Recovering, Star Dancer questions how Pinkie Pie can be present, only for Pinkie to question how Star Dancer herself can be there. In the course of their conversation, Star Dancer deduces that Pinkie Pie has somehow become "unstuck" from time, which is also how she was able to enter Star Dancer's subspace pocket. She also inadvertently admits that she is, in fact, a Future Pony.

Pinkie then questions whether Star Dancer has seen the alternate Dr. Hooves, and she reveals that he and his Derpy are trapped in bubble that keeps them outside of time. Pinkie Pie inadvertently lets time resume for the pair, though they remain confined, and Star Dancer then reveals that she held them captive on the orders of her master: an alternate version of Dr. Hooves named [Professor What. After some name-related shenanigans, and an explanation of the Professor's rather petty rivalry with the doctor, the Professor zeroes in on the anomaly that is Pinkie Pie. He questions how she can be unaffected by the time loop, given his "perfect" Ouroboros equation, when alternate Derpy points out that he failed to carry a two in his math.

Pinkie confronts the Professor for her confinement in the time loop, and he reveals that he actually intended to cause the day of the Great Cake Bake to repeat endlessly. The culprit behind the day before the festival being repeated, as it turns out, is the alternate Dr. Hooves.