Spinal Leech (Infestation, Vermin) CR 2
These vermin appear as 3-inch-long transparent leeches. A typical encounter is with a swarm of 10–20 leeches. They are found in marshes, stagnant underground pools, and swamps. They attach to their prey and drain spinal fluid, inducing paralysis in the victim. When first encountered, a DC 15 Perception check can be made to notice them in time to avoid them entirely. If this check fails, the spinal leeches go unnoticed and crawl onto their victim, moving quickly to the spine. A spinal leech needs only a single round to reach its destination on a Medium creature. If the target is wearing medium armor, it takes an additional round; two rounds are added if the victim is wearing heavy armor.
When a leech attaches itself, the victim may attempt a DC 15 Perception check. If successful, he feels a strange sensation run down his spine; otherwise, the leeches go unnoticed. Each round thereafter, a DC 17 Fortitude save must be made or the victim takes 1d6 points of Dexterity damage. At Dexterity 0, the victim is paralyzed until his Dexterity score is brought to 1.
An application of fire or salt instantly kills all leeches. They can also be pulled from a host with no ill effects (pulling a single leech off is a move action that provokes attacks of opportunity).
Spinal Leech from the Tome of Horrors Complete, Copyright 2011, Necromancer Games, Inc., published and distributed by Frog God Games; Author Scott Greene.