The Spirit of Chaos is bored whilst wandering the long halls of Canterlot Castle. He finds Celestia's room and in turn discovers something that will change Discord's perception of the Solar Princess.
This is first and foremost a Fat Fetish story, containing, Morbid/extreme obesity and light slob (Messy eating, sweat, light burping)
Original picture is by the great AstroZone
I certainly enjoyed this weight gain story.