The Strange Bestiary
A "naked" polymous looks like a muscular worm of wet, veiny tissue, bristling with hairlike filaments that it uses as nerve endings. Its mouth looks almost human, complete with tongue and teeth, and two eyestalks emerge from the top of its head. Usually, however, polymous are clothed in the skin of someone they've replaced. A polymous sheds its covering only when a skin becomes too damaged, whereupon it slithers free.
Many in Ruk know of the polymous, but they keep that knowledge close. No one is sure who has been replaced and who hasn't, so those in the know stay silent. No one is quite sure why the polymous have infiltrated Ruk society. The few that were discovered and analyzed didn't reveal much, other than to indicate that they serve "another."
A polymous can be anyone, anywhere in Ruk. Parasites, they enter their victims' bodies, liquefy the innards, and expand themselves to wear the skin as if it were clothing. Aside from a little seepage around the point of entry—nose, mouth, ear, or elsewhere—they look, act, and behave as the people they replace.
Motive: Infiltrate societies, steal scientific discoveries
Environment (Ruk | Weird Science): Any populated area
Health: 18
Damage Inflicted: Moderate wound (4 points)
Armor: 1
Movement: Short
Modifications: All tasks related to deception as level 5.
Combat: A polymous fights using whatever weapons its host possessed before it was killed. If the creature takes 9 points of damage in battle, the polymous wriggles free of the skin, leaving the useless sheath in a heap on the ground (losing its 1 point of Armor in the process), and springs toward its foe as part of the same action. If it attacks a target who was not aware of the true nature of the polymous, the difficulty of the target's Speed defense roll is increased by two steps due to the surprise, and if the polymous hits, it inflicts a moderate wound (6 points) on this attack.
Normally, the attacks of a "naked" polymous inflict a moderate wound (4 points) as it attempts to force itself into the target's body through the mouth, nose, ear, or whatever orifice is available. It can't enter the body until the target has become impaired. After that happens, each successful attack requires the target to make another Might defense roll. On a failure, the polymous enters the target. Each round the polymous remains inside the body, the victim moves another step down the damage track as its liquefied organs leak from its orifices. When the victim dies, the polymous assumes the creature's identity.
A polymous is vulnerable to electricity, taking 2 points of damage for each point of electrical damage inflicted.
Interaction: A polymous is a skilled infiltrator and plays whatever role its host played when alive. The polymous knows enough of what its host knew in life to get by, but it can't stand up to suspicious scrutiny.
Use: A polymous replaces one of the PCs' allies and secretly gathers intelligence. It has the same emotional and memory connections to the PCs that the character had before being killed by the parasite, which could create some tension (especially if the victim had an amorous connection to another PC in the group).
Loot: If the replaced person had something of value, the polymous now has it.
Removing a polymous that has entered a victim but not yet killed her is a tricky business if one wants to keep the victim alive. One possible method is to use electrical attacks' though electricity may harm the victim, it hurts the polymous more. When a polymous is not taking over a host, it is typically about the size of a human arm.
GM Intrusion: The sudden emergence of a "naked" polymous from the skin of a victim requires that he character succeed on an Intellect defense roll or lose his turn in horror and surprise.