when I was a kid, I used to believe there was a vampire under my bed. I came to believe that if I willingly offered some blood he would not take it and kill me in the process. I would puncture my leg with a thumb tack and dribble it into the cap of a water bottle and slide it under my bed. I stopped when my parents saw the dots and yelled at me.

The thing is, every morning the cap would be clean and empty like no blood had entered. What happened?