Per 
SCP# 8829 453
For purposes of simplified identification this anomaly has been code named: "BLACK-BIRD"
Anomaly is neither human nor creature, it is an entity that exists outside the boundaries of space and time. BLACK-BIRD doesn't exist on our physical plane, but in order to take any physical form on our plane must use a human or humanoid mind as a rudimentary anchor. How it found entry into our world to begin with is still unknown. It infects a mind simply by inciting fear in compatible minds. However, it can only use one anchor at a time meaning that fear is only one half of the puzzle, the other being if there is a need for transfer.
Infection occurs over the course of three stages:
STAGE 1: (2min-3hr) The host will begin to experience mild auditory hallucinations, including (but not limited to): Bird vocal noises, Echoes, Whispers and Distant screams. The earliest sign of infection is typically a discoloration of the host's iris's. Which may very from pale grey to crimson red.
STAGE 2: (4hr-12hr) An apparent loss of character or notable disassociation, ie: out of character actions, mood swings, memory impairment, and in some cases even referring to themselves by the alias "BLACK-BIRD".
STAGE 3: (12hr-14hr) As stage three takes effect the hosts body will begin to lose both muscle and overall body mass. Their arms and legs will grow longer, but more brittle. At the end they will lose skin coloration and they will no longer retain any control over bodily functions. At this point the anomaly has ceased full control of the host.
BLACK-BIRD can alter reality around him to an undetermined extent. Many who have faced him described the experience as "mind melting" and "lonely". The anomaly has only one weakness in that it can only infect one host. The host must remain sedated and alive at all costs, if the host is compromised via poor health or other causes then it is imperative that a transfer be overseen. The moment said transfer is complete, it is vital the new host be immediately sedated and contained.
