This strain of Contagion creates a new organ, limb, or other body part in its host, like a slowly growing tumor. It manifests in stages.
The first stage is inadvertent and uncontrollable. This first stage mutation takes three failed breaking points to reach its fully-grown size. Until then, the person suffering from this condition has the Sick Tilt (Chronicles of Darkness, p. 93) to reflect their state. After the first growth has fully manifested, a new mutation develops, and the process starts over again. For each breaking point the infected goes through, one dot from the character’s Social Attributes moves to a Physical Attribute of the player’s choice. Social Attributes can reach as low as 1 in each trait, at which point start moving them from Mental Attributes of the player’s choice.
Although the victim may not necessarily desire another mutation, they have a chance to stave off its development. Whenever the shapeshifter changes form, they must roll their Stamina + Resolve. If they fail, a full physical mutation bursts free. This could be in the form of scaled skin, a new limb, another eyeball somewhere on their body, a set of mandibles, or worse. If such a mutation occurs, it removes the shapeshifter’s ability to use one of the alternate forms from them.
For each mutation, shapeshifters infected with this strain suffer a –2 dice penalty when attempting to control which form they shift into. This cumulative penalty ultimately makes Uratha, Beasts, and other shapeshifting creatures incapable of changing.
Possible Sources: The Geryo strain of Contagion when infecting a shapeshifter.
Resolution: The Contagion must be eliminated from the host using a purified weapon or artifact. Though this may kill the infected, it also eliminates Contagion.
Beat: The character accepts a breaking point without resistance and does not recover Willpower.