Sketch: Surprise Pie (Patreon)

Surprise Pie was the fifth (and very unexpected) daughter of Cloudy Quartz and Igneous Rock Pie.  Produced when her parents were getting way on in reproductive years, Surprise was a latent pegasus via her paternal grandmother.  Undeterred by the knowledge that her sister would never fly, young Pinkie was delighted to have a new eventual playmate.

Surprise only survived a couple of days.  All of the sisters were devastated (to say nothing of their parents, whose despair would lead them to work themselves to death).  Pinkie, Maud, Lime and Marble each has Surprise's name tattooed on her body.  Surprise was not and would never be forgotten.