Once there was a nice old lady who had a lovely little dog. One day, the old lady heard on the radio that a crazy murderer had escaped from jail and that she should lock all her doors and windows. So she locked every door and window in the house except one tiny one to let some air in. She thought that a murderer would never get in through there.
So that night she went to bed as usual. She knew everything was okay because when she put down her hand the dog licked it. But later in the night she heard a drip, drip, drip. She put her hand down and the dog licked it and everything was okay, so she went downstairs to check out the tap. But the tap wasn't dripping. So she went to bed again. And everything was okay. She woke up again later in the night, though, so she thought the dripping sound must be coming from the shower. She went into the bathroom, and there was her dog, dead, hanging in the shower, dripping with blood, all its intestines hanging out. Written on the mirror was: "Humans can lick, too!" And behind her in the mirror, she saw the murderer.