Blights often adopt multiple forms in order to propagate their infestation. Sometimes humanoid modosophonts may be corrupted and augmented into a deadly and formidable infective agent, as here.
A malign, morally and ethically dangerous transapient entity that attempts to subvert or seize control of other entities, in order to increase its own power. A Blight may infect a non-sentient autonomous system, an intelligent agent, sophont or even a transapient of similar (or lower) toposophic level than itself. Generally speaking, a Blight is something that expands and turns other entities into beings like itself. Blights can be distinguished from Perversities, which do not seek to assimilate or subjugate other entities but instead seek only to cause damage and destruction to other sophonts, to their cultures and their infrastructure.
A Blight may consist of (or utilise) a virus-like infomorph capable of infecting a suitably complex processing system, a transapient-level replicating swarm, a complex single entity such as an Intelligent Superobject or a fleet of such objects, or even an entire transapient-led culture with a pernicious memetic belief system.
Unlike a sub-transapient malware attack or natually-evolved biological disease, blights use transapient level strategies and tactics. However, the objectives, motives and behaviour of a blight may be completely incomprehensible; often a blight will effectively become an animin god, even if it was not originally such a being.
A blight will often attack entities that are less than transapient, but only to turn them into tools, avatars or servants for itself. Blights are often more obvious than perversions, but still able to field a large array of nasty tricks.
Examples
The Hypercorruption Expanse developed from a Metasoft exploration vessel that was infected by a high toposophic virus of obscure origin. After a protracted conflict with the surrounding cultures, the Expanse fled to the Periphery, where some believe it still lurks.
The Geminga Orthodoxy was a blighted version of the mainstream Conver Ambi culture, led by a S:1 transapient which worshipped the Geminga pulsar and was obsessed with the hopeless task of destroying the influence of the Sephirotic archailects. The Orthodoxy was destroyed utterly during the Consolidation wars.