Two dorm-mates in college were in the same science class. The teacher had just reminded them about the midterm the next day when one dorm-mate — let's call her Julie — got asked to this big bash by the hottest guy in school. The other dorm-mate, Meg, had pretty much no interest in going and, being a diligent student, she took notes on what the midterm was about. After the entire period of flirting with her date, Julie was totally unprepared for her test, while Meg was completely prepared for a major study date with her books.
At the end of the day, Julie spent hours getting ready for the party while Meg started studying. Julie tried to get Meg to go, but she was insistent that she would study and pass the test. The girls were rather close and Julie didn't like leaving Meg alone to be bored while she was out having a blast. Julie finally gave up, using the excuse that she would cram in homeroom the next day.
Julie went to the party and had the time of her life with her date. She headed back to the dorm around 2 a.m. and decided not to wake Meg. She went to bed nervous about the midterm and decided she would wake up early to ask Meg for help.
She woke up and went to wake Meg. Meg was lying on her stomach, apparently sound asleep. Julie rolled Meg over to reveal Meg's terrified face. Julie, concerned, turned on the desk lamp. Meg's study stuff was still open and had blood all over it. Meg had been slaughtered. Julie, in horror, fell to the floor and looked up to see, written on the wall in Meg's blood: "AREN'T YOU GLAD YOU DIDN'T TURN ON THE LIGHT?"