This comic is based on MLP comic #57, in which Pinkie Pie absorbs the energy of The Chaos Realm and replaces Discord as Princess of Chaos.

It's a really fun and creative story, and this is a 'what if' scenario where Pinkie successfully defeated Discord, absorbing his power and bringing her never-ending party back to Equestria. She begins by turning Canterlot into a big rock candy mountain, and the castle itself into a cake! A pity that Celestia had to show up, though. Princess Pinkie has little tolerance for party poopers...