The blightspawn may look like a giant mosquito, but it’s far more deadly. Not only is it man-sized and man-smart (a not-bad Int 7), it’s also got a poison sting, a stagnation aura that lulls its victims into torpor, and spell-like abilities—including bestow curse, blur, and contagion—even many druids would envy.
But its neatest party trick is its ability to gestate for years and even decades inside a human host. The blightspawn was originally introduced as the blightspawn of Ghlaunder (courtesy of the adventure Feast of Ravenmoor) and they are a combination boon/weapon from Golarion’s demigod of parasites and disease. A cultist carrying a larval blightspawn may nurture the aberration his entire life, only hatching the creature in death…and all his children may be likewise so favored. In your campaign, blightspawn might serve a similar god of disease, a Horseman of the Apocalypse, demonkind, or an evil plane itself. Or blightspawn might just be a natural (if truly horrific) parasite, with no divine strings attach. Fantasy worlds can be buggy like that.
One last note: A lot of GMs struggle with making character death scary in a raise dead world. Having a character’s corpse birth a blightspawn (and all the complications for resurrection that implies) could be an ideal way to ratchet up the fear level.
Three separate groups of pilgrims embarked from Brighton today through the Gate of the Faithful…and one of them is hiding a pupating blightspawn among its number. Adventures must attempt to suss out which band of pilgrims the ailing cultist is hiding among and apprehend the would-be aberration.
A remote stronghold struggles to contain an epidemic of thorny vines that seem intent on walling off the barony. The glands of a blightspawn could be used to ward off the vegetable horrors and even stunt their growth (as per diminish plants). Adventurers in search of these components follow disturbing rumors to a town given over to the worship of parasites, where every adult lives in service to—or as a future meal for—one entity or another, including several blightspawn.
An adventurer isn’t trying to stop a blightspawn—he intends to become one. Raised by cultists from birth to worship the Maiden in Shrouds, the adventurer leaps into battle believing his death will only hasten the birth of the moth-winged avatar inside him. If he succeeds in being slain in combat, he will leave his companions fighting one more monster. Assuming they bring him around to the worship of another deity before this happens, the next challenge will be safely extracting the larval blightspawn from inside him.
—Feast of Ravenmoor 29 & Pathfinder Bestiary 5 43
Another canceled flight. Another night in Minneapolis. Uff da.