We first glimpse this pallid, featureless humanoid in the premier episode and it makes quick use of a metallic drill-like phallus. We can naturally attribute its color and atrophied eyes to its status as a troglobite: an obligate cave-dwelling organism. We've explored the science of such organisms before in our discussion of certain Appalachian crawlers, so let's instead focus on that murderous sex organ.
Bed Bugs and Demons
Most fittingly, this hotel horror reminds us of the common bed bug Cimex lectularius. Males of this species engage in traumatic "extragenital insemination," utilizing a specialized hypodermic phallus to pierce the female's abdominal wall and ejaculate directly into her body cavity. The sperm then migrates to her ovaries. In fact, the female's genital tract is never used for copulation; just for egg-laying [source: Stutt and Siva-Jothy].
Fortunately, female bed bugs evolved a special organ called a spermalege as a counter-adaptation. It consists of an external, grooved opening called an ectospermalege and an underlying sac called a mesospermalege to collect the seed and even weed out any unwanted contributions. When a male bed bug penetrates another male, however, there's no preexisting wound to reduce traumatic injury. As such, they produce special pheromones to ward off unwanted copulation.
So don't judge the Addiction Demon too harshly. His way is perfectly natural.
Monster of the Week is a - you guessed it - regular look at the denizens is of our monster-haunted world. Sometimes we'll focus on the cultural aspects, but mostly we'll look at the possible science behind a creature of myth, movie or legend. Be sure to explore the Monster Gallery as well as the Monster Science video series.