Magic degeneration, a very uncommon and very much uncureable unicorn disease. Majority of the patients don't make it. My nephew has that disease, and he's made it further along than anypony else. This is his story.
I may not make the best, but I try the best. I may not be a completionist, but if I like the story I'll read it through to the end. I'll help edit if needed. feel free to pm me if you do need help.