A less-known and less horror-movie centric bit of vampire canon is that they suffer from arithmomania, a form of obsessive-compulsive disorder that presents itself as a need to count objects in your surroundings. This crossed even cultural boundaries, with tales of number-crunching Counts existing from Slavic lore all the way to the Chinese jiangshi.

As the lore goes, the vampires could be distracted from your pulsing, delectable carotids by a surplus of something in the surroundings that demanded to be counted. Holes in a fishing net, seed scattered at the door, Chinese folklore even recommended tossing out a handful of rice grains in front of a vampire as a functional defense against getting feasted on.

One! One grain of rice!