Colloquial Terms: The Dying Man, the Lost Man, All and None, the Decay, Jumper, VAGRANT, He Who Seeks Shelter
Physical Characteristics: None, though victims do exhibit signs of necrosis and occasional deformities
Behavioral Characteristics: Lacks a physical body, but inhabits the bodies of others. Once it has entered a host body, the host begins to decay. Symptoms of PRE15's infection include necrosis and a variety of deformities including, but not limited to, the growth of extra limbs or digits, scales developing along the skin, development of extra organs, and cancerous growth of skin and muscle cells. The speed of decay varies from victim to victim, ranging a few hours to a few years. Psychological effects on hosts also vary. Some hosts appear to lose all signs of previous personality as PRE15 takes control, others appear normal except for occasional episodes of erratic behavior. A small number have been reported as having gone comatose. When the host body has decayed to the point that it is no longer feasible for PRE15 to inhabit it, then PRE15 will seek to make physical contact with another organism, jumping into the new body. There are some reports that PRE15 is able to split its consciousness and infect multiple bodies at once, though these reports are unconfirmed.
Though PRE15 currently possesses no body of its own, there is evidence to suggest that this was not always the case. NOTE: That evidence is classified. --SΣ
Further Reading: This blog as well as this blog, both concerning the same victim of PRE15