Uh, okay. How about this? Discord showed up, and laughing a maniacal laugh, put eyepatches on everypony's left eye. Now, everypony could only half-see, except for the ponies who only had a right eye, who were unaffected, and ponies who only had a left eye, who were rendered completely blind. It was a terrifying time of tribulation, it took the combined strength of Celestia and the Elements of Harmony to restore order to the land.