They are – the precursor species for the Kum. Unlike their progeny the Kum, this giant slug wears its host body — the body must be that of a female’s cadaver. Preferably, it’s the corpse of a freshly-killed Crone.
They’re the basis for the “imperfect” vampires in “The Strain” book series co-authored by Guillermo del Toro and Chuck Hogan. Klapp are one of the seven Parasite propagator species born from the blood of the fallen angel Ozryel.
Known as the archangel of death, Ozryel became consumed by bloodlust after being sent to destroy the cities of Sodom and Gomorrah for their wickedness. He was punished by having his body severed into seven pieces. Ozryel’s head is from which the Klapp are said to have spawned.
Once situated, Klapp resemble a long, retractile proboscis beneath the host’s tongue that reaches up to six feet from the mouth. When it deploys itself as a “stinger” for feeding by latching onto a prey’s throat, forearm, or thigh, draining the victim’s blood for sustenance, it is also infecting the victim with capillary worms. These worms secrete a venom which mimics the combined effects of a highly addictive narcotic akin to the designer street-drug known as “Red” and an hallucinogen as mind-shredding as LSD-4. The venom, in effect, chemically lobotomizes — rendering the dosed a mindless, wanton, and sexually insatiable filler — literally, a fucking placeholder. Asylums, that use it illegally to sedate “troublesome” patients, euphemistically call it: “putting a patient to sleep” or even more cryptically “doing the 12-monkeys with a patient”.
After the extensive transformation of the host body to make it suitable for the Klapp’s residence, the host’s jaw is set at a much lower hinge. While the host’s mouth is gaping like a snake’s when the stinger is deployed, the host is incapable of physical speech.
Not people. Not sentient. Parasites. Ancient Ones. Hideous monstrosities who begot all blood-sucking parasite creatures of their supernatural ilk. Carnal. Covetous. Being mindless and sexually insatiable, these wanton blood-sucking parasites are more akin to zombies than “traditional” Vampires — all they feel is hunger and lust.
They are not Vampires, of course. But, they are vampires, nonetheless.