As an introduced species, descended from the common rat and long since adapted to the conditions of the plane, vapor rats are able to gain most but not all of their nutrition from the vapors of Smoke. The remainder must be gained from food and drink as any normal creature - vapor rats are omnivorous, but given the choice they prefer meat over other forms of food.
Undomesticated vapor rats tend to travel in small swarms, no more than 6-8, using their numbers to better hunt the various birds that also make their home in the plane. Even in the wild the vapor rat is still fairly docile, preferring to dissolve itself or, if necessary, run rather than fight an opponent that obviously outmatches it.
Vapor rats appear much as the traditional rat, but more insubstantial, and with the appearance of thin tendrils of smoke constantly rolling off their backs, or a distorted haze in the air above their bodies. Skin and tail color are always pure black, while fur color varies from pitch black to light grey, and size can vary from 4 inches long for the youngest up to a foot long for adult vapor rats, females being slightly smaller than males, with tails always near to the same length as the body. In gaseous form, vapor rats can be anywhere from nearly invisible to a small roiling cloud of dark smoke.
- Denizens of the Inner Planes
- Inner Planes, The, pg. 89