An outbreak of lice breaks out in Ponyville's elementary school, only to be quickly shampooed out of existence. But who other than Fluttershy should find herself hosting them after the initial panic dies down? Convinced that protecting these lice wouldn't harm anypony else—as had been the case with Applejack's bat problem—if she were careful—and would definitely not be a repeat of the Parasprite incident—Fluttershy decides to keep them in her mane.