These horrific parasites live and breed in tainted water, and can infest any creature that drinks from affected lakes, rivers, and pools. When these microscopic parasites enter a humanoid creature’s intestinal tract, they take on an unholy life. Within 2d4 hours after ingesting bowel worms, the victim must attempt a DC 15 Fortitude save. Success indicates the victim harmlessly digested the bowel worms, but failure causes the victim to suddenly cramp up, suffering horrific intestinal pain that causes him to become staggered. The victim also takes 1d4 points of Constitution damage each round until he’s taken a total of 4 points of Constitution damage. A full-grown bowel worm then burrows from his belly and crawls out onto the ground—a pallid, arm-length, maggot-like, eyeless worm with a nasty collection of toothy mouths on one end. Once a bowel worm escapes, it is helpless and can’t move. Dealing it any amount of damage, such as by stomping upon it, kills it. As it dies, it emits a high-pitched shriek like that of an infant in mortal pain.
After the victim passes the bowel worm, he takes 1 point of bleed damage, but is no longer staggered, and takes no further Constitution damage… at least for another 2d4 hours, whereupon the victim must attempt another DC 15 Fortitude save to prevent another bowel worm from maturing and burrowing free. These saves continue until the victim succeeds at a saving throw (at which point the infestation is over), or until the victim dies.
The fact that these horrific parasites mature only within humanoid hosts, and that they seem to serve no real purpose once born except to die, has long vexed sages.
In truth, these wretched worms are a true manifestation of the Abyss—life that exists only to cause misery and pain. Bowel worms are an infestation—remove disease or any other effect that cures diseases removes them, but immunity to disease offers no protection, as the affliction itself is caused by these horrible parasites.
Pathfinder Campaign Setting: The Worldwound © 2013, Paizo Publishing, LLC; Authors: James Jacobs, Jonathan Keith, Jason Nelson, Todd Stewart, and Tanith Tyrr.