Cranial Leeches

Cranial Leeches are alien grub-like creatures have been linked to many mysterious deaths and heretical actions across the Askellon sector, when individuals have acted against all previous accord or rationality.

Legends have that some grotesque species grows the leeches, which detach and seek out sentient life as their prey. Others hold that the leeches are bioengineered weapons from some unknown race that either departed Askellon long ago, or uses the leeches as part of advance forces. Most tales relate that once a leech implants itself inside cranial tissue, either slowly insinuating itself under skin or forcibly burrowing though eyes or other soft entry points, its host falls under alien domination or is easily manipulated by any around him.

Some accounts have the leeches originating along Thule's trailing edges, from one of the many worlds still unexplored in Wilderness Space there. Many believe, though, that they are grown in vats and sold through the Faceless Trade, and several Inquisitorial actions have been made to find and destroy these sources or gain control of them for use in interrogations. While some raids have been successful, the continued appearance of the leeches across the sector indicates other sources still remain.

A leech can be applied to a person's skin, and requires roughly five solar minutes to agonisingly make its way into a brain and spread its tendrils across neural tissue. The host becomes highly suggestible, and carries out any instructions without hesitation unless they are immensely strong of will.

To an onlooker, a victim might also begin acting oddly, performing actions that could represent the orders of his alien masters.

Removing an implanted leech (without damaging the host) requires intense medicael skill and ability, as the leech causes irreparable trauma to the brain at the slightest failure. Otherwise, if there is no concern for the host's wellbeing (or continued life), a leech can be forcibly and easily removed. Removed leeches die within seconds, no matter the means used.

Source
[[Category:C]]
 * Dark Heresy (2nd Edition): Enemies Without (RPG), pg. 59