These little guys live in a low light environment -- generally caves, hence the milky eyes and general lack of pigment to their skin. They're not blind, but are very easily startled by bright lights and loud noises. In fact, despite being predators, they're extremely jumpy and easily scared creatures. This is unfortunate, because once cornered, the cartilage attached to their jaw expands out to both sides to form the mouth that you see here, exposing the threat to their extremely toxic saliva. In addition to being toxic, it is also a mild paralytic. They can projectile spit large gobs of it at their enemies or whatever it was that startled/threatened them. The hissing noise that they make when startled echoes through the caves where they live, sounding rather ghostly to passers-by and is the origin of the "specter" part of their name. The "spitting" part of their name is, well, fairly obvious. Especially to any unlucky adventurer that crosses paths with one.
They feed on bats and smaller rodents. In recent years, they have been known to perch on a rocky outcropping where bats are flying around and simply open their jaws wide until they catch a bat in their gaping mouth.