Software/nanotech perversion of nanocytes or nanochondria of beings or objects with symbiotic nanosystems.
While large-scale perversions gain the most publicity, small outbreaks of opportunistic or expansionist alife are far more common. One form of minor perversion that has recently emerged as a serious threat is sentient cancer.
Sentient cancer is a software/nanotech perversion of the nanocytes or nanochondria of beings or objects with symbiotic nanosystems (mainly cyborgs and vecs, but most bionts in developed systems carry some nanosystems). Subverted nanosystems disobey their original programming, attempting to spread and reshape their hosts according to their own patterns. Non-sentient outbreaks are usually quickly detected and corrected, but sentient cancers are often both subtle and able to defend themselves. Quite often the defence consists of replacing vital tissues with cancerous tissue, making any removal attempt life threatening. Instead of overwhelming the cancer with invading immunities more diplomatic or subversive strategies have to be employed. In some cases the cancer can be convinced to migrate to a new environment, or its underlying pattern subverted by AI viruses, memetics or cultural engineering.
Sentient cancers quite often emerge from dense embedded single-purpose AI systems such as advanced "intelligent immune systems" which undergo a sentience plague as specialized AIs become individualist and despecialize. Unchecked sentient cancer can spread to other beings or objects, infiltrating nanoinfrastructures and resulting in a full-scale blight. However, most infections are self-limiting to their host or even parts of the host.
After the Vela Outbreak, sentient cancers have migrated away from the Vela Immunity, accidentally spreading to other worlds. Attempts by the Accidental Sentience League to aid the victims and give political asylum to the Vela cancers have so far had limited success and stretched its resources in the region to the limit.