The xenomorph strain transforms the target’s body in addition to their mind. It is only spread as a biological nanovirus or nanoplague (not as a digital virus or basilisk hack). Over time, the victim’s morph physically transmogri es into some sort of alien life form. Different variants of this strain produce different xenomorphs. It is not known where these different alien templates originated, meaning they may be copies of (once) existing alien species or simply neogenetic creatures created from scratch. The one trait they have in common is that they are universally dangerous. Some speculation in Firewall circles suggests that the exsurgent virus may in fact have a “library” of creature types to deploy, under the assumption that at least some will be more effective than others for exterminating whatever victim species they are fielded against.

This strain follows the same rules as the haunting virus (above), but with the following changes. The timeframe is typically much quicker.

Stage 1

The effects from Stage 1 of the haunting virus apply. Additionally, the character begins to suffer minor physical changes that are de nitely unusual but are not impeding in any way and are easily hidden from others. Example biomorph alterations might be: unusual hair or brous growth, some skin discoloration or translucence, severe rashes, dermal thickening, weakened or enhanced sensory organs, strong body odor, hair loss, teeth gain or loss, vestigial tail or other limb growth, minor dietary changes, and so on. Synthmorphs might experience minor system glitches, malfunctioning or improved components, and spots of material stress or trans guration. Gamemasters are encouraged to be creative. This stage typically lasts from initial infection to 1 week for biological nanovirus strains, or from infection to just 1 hour for nanoplague strains.

Stage 2

As with haunting virus Stage 2, plus the character begins to seriously transmogrify in ways that are dif cult to hide from others, becoming more and more monstrous as the stage progresses. Example biomorph transformations include: growing scales or feathers, partial modi cation of limb structure, partial new limb growth, vestigial sensory organ growth, sensory loss, extension of claws or spines, severe dietary changes, etc. Synthmorphs might experience radical system and shape alterations, limited or enhanced sensor functions, or even conversion of their robotic shell to smart materials. These physical changes weaken the victim, in icting 1d10 physical damage. This stage typically lasts 1 week for biological nanovirus strains or just 1 hour for nanoplague strains.

Stage 3

As with haunting virus Stage 3, a character reaching this stage becomes an NPC. Additionally, the victim completely undergoes a transformation into some sort of creature that is no longer even remotely human. Example exsurgents of this nature are detailed on p. 367.