DISCLAIMER: This story takes place in an alternate reality. Some of the plotlines that are canon in the show, will not be canon here.
The Pie family lived on a small rock farm, until a misfortunate event caused the family to split apart, with the father, Igneous Rock, staying on the rock farm with his two daughters, Maud Pie and Marble Pie. While the mother, Cloudy Quartz, moved to Ponyville with the other two daughters, Limestone Pie and her youngest daughter, Pinkie Pie, who might just be out of her mind.