Vampires!!!!

I think my bike was attacked by vampires yesterday on my way to work. This morning was the first chance I had to change my tube, and when I did I found two puncture marks, each the same size and shape right next too each other. Sadly I forgot to take photographic evidence. Also I think the vampires are the ones responsible for the fact that my bike always comes back from the shop with no end caps on my valce stems. I think secretly they'd love it if the valve stems were damaged.