Dark humor with: Your little sister, Milk.
There was a little girl who was saying her prayers as her dad walked past her room. “Goodnight mommy, goodnight daddy, goodnight grandma, goodbye grandpa.” She said. The dad thought nothing of it and went to sleep. The next morning the grandfather was dead. The best night he heard his daughter praying again. “Goodnight mommy, goodnight daddy, goodbye grandma.” She said. The next morning the grandmother was found dead. Now the dad started to worry. His name was next so would he die? That night when he walked past his daughters room he heard; “Goodnight mommy, goodbye daddy.” That night the dad couldn’t sleep but eventually was able to. He awoke the next day and found his wife in the kitchen crying. “What’s wrong?” He asked. His wife looked up at with with tears in her eyes. “The mailman’s dead...”