Miss Hoover:  Children , I wo n't be staying long . I just came from the doctor , and I have Lyme disease . Principal Skinner will run the class until a substitute arrives .
Ralph: What 's Lyme disease ?
Principal Skinner: I 'll field that _ one _ .
Principal Skinner: Lyme
Principal Skinner: disease is spread by small parasites called ' ticks ' .
Principal Skinner: When
Principal Skinner: a diseased tick attaches itself to you , it begins sucking your blood ...
Miss Hoover: Oh ...
Principal Skinner: Malignant spirochetes infect your bloodstream , eventually spreading to your spinal fluid and on into the brain .
Miss Hoover: The brain ? Oh , dear God ...
Class: Wow .