Per 
[Subject to change.]
Site 104 experienced a site-wide lockdown on 09/18/1987, initiated by the East Wing of the Research and Development sector of the Site. After losing contact with the sector for over thirty minutes, Mobile Task Force Unit Upsilion-137 ("Broken Faith") was dispatched to assess the situation and contain any threats, armed with incendiary weapons, short-range EMP equipment, and biological hazard suits. When the unit entered into the area, they were met by Foundation personnel who had developed various visibly anomalous visible traits, reportedly; white feathery wings, extra limbs, extra eyes, and ██████, with ████████ morphing near the chest. Some personnel were also seen affected by more than one of these traits at a time. After attempting to aid the affected personnel, they instead demanded termination and appeared to be in excruciating pain. After relaying the situation to Site Command, Site Director ████████ authorized the termination of all personnel. It was discovered that SCP-XXXX's containment chamber was closed and the medical freezer was fully operational and had not been opened. Use of the EMP equipment has shown to be effective at neutralizing instances of SCP-XXXX-B. After terminating the personnel in the wing and charring the remains, an all-clear was announced. The amount of personnel lost is unclear.
A data download from the Research and Development server indicated that around 08:43, multiple vital signatures of Foundation personnel were lost, suggesting that an object had breached containment. The automatic lockdown failsafe did not trigger however, as a majority of vital signatures in the sector were still present as a result of SCP-XXXX-B not terminating the victims outright. Reconfiguration of Foundation personnel vital signature monitors and the automatic failsafe have been made. Exploration of the wing found what appeared to be a Foundation standard PDA belonging to Dr. Salvadore in an empty containment cell, containing a recently uploaded audio log.
BEGIN AUDIO LOG
[Heavy breathing can be heard, the blaring of Foundation alarms sound in the background unrelentlessly. Doctor Salvadore clears his throat and begins to speak shakily, appearing to be traumatized and in pain.]
"W-We were analyzing the.. err..”
[A obscure sound of a heavy metal object can be heard as the doctor presumably attempts to compose himself. The faint spark of a cigarette lighter is barely heard, although not believed to be the source of the previous sound. Doctor Salvadore breathes in heavily, and sighs.]
“Our team was analyzing the nanomachines, we tried to e-extract any data that could be inside, b-but we don’t yet have the technology to connect to whatever it is. I was observing SCP-XXXX-A under a microscope along with samples of human tissue. I began to notice the bacterium activate, despite it b-being separated from the ‘host’, editing the genetic structure of the tissues. I rose up to tell my colleagues, only to find them all in..
[Doctor Salvadore pauses for a second, breathing in and out. Distant screams of terror and gunfire can be heard in the background. The pulsing of more than one heart can slightly heard.]
"L-Let's say, pure terror. Every single person in that lab f-froze in p-place just for a second. Many of my best researchers in a state of pure panic and some losing consciousness. It appeared that the bacterium activation wasn’t an isolated incident, and some started to.. convulse and collapse in pain."
"The sight of it. The utter sight of horror.."
"The utter sight of horror unimaginable to the human mind befell on all of us. Some developed wings, others evolved their lungs into gills and drowned on dry land. Others, I assume, that the bacterium caused mutations faster than the body could handle, or used up too much of the body’s energy at once, and promptly fell onto the floor, convulsing and foaming at the mouth, expiring before any visible changes took place. They were the lucky ones."
"Something went wrong.. of course, f-fucking captain obvious.. we.. I don’t know what went wrong, perhaps we activated the nanomachines while they were away from the host, or erm.. well, there’s no way to tell. But, the effects they had on researchers were.. ungodly, to say the least. I’m surprised I’m still alive. My internal organs are bleeding out, trying to adapt to SCP-XXXX-A’s effects and the.. pain.. My God, the p-pain… The goddamn-”
[Doctor Salvadore kicks the sides of the containment chamber with incredible force, letting out bloodcurdling screams after doing so. Eventually, his screams are drowned out by the less distant screams of his co-workers. A long pause follows for thirty seconds, being interrupted by the sound of a loading firearm.]
“We all went through decontamination each time we entered the chamber and handled samples of inert SCP-XXXX-A. Every. Fucking. Time. And now I've got scales growing on my back, and fucking fur on my fucking-”
[Doctor Salvadore pauses and takes a deep breath, each one sounding more and more laboured. The pounding of a metallic door can just barely be heard in the background. After repeated pounding, the door falls onto the floor in a loud crash, startling the dying doctor.]
“Oh, and here they come. Not a moment too soon. Not like I have.. long anyway. Many of my colleagues already succumbed to the.. and.. m-my colleagues.. my colleagues.. I'm sorry.. I'm sorry..”
[Doctor Salvadore mutters the same two words over the course of a minute before a sudden and loud discharge from point-blank range is heard. The only sounds received by the PDA at this point are of Mobile Task Force operatives using incendiary weapons and conventional weaponry in the laboratory, and frequent screaming. The audio log stops recording at around seven minutes, presumably as a result of the use of short-range EMP bursts.]
END LOG
After an investigation of what remained of the Research and Development Department, Site Command has found records of inbound outside communications from outside the Solar System, dated approximately after testing of SCP-XXXX was approved. These messages weren't recorded in the main database for unknown reasons, thus was not made aware of by any security personnel. The purpose of the messages appears to claim ownership of the object, which the Ethics Committee has stepped into. After the Foundation's best attempts at translation, a rough transcript is as follows:
HELLO
RETURN [unintelligible] TO ITS PRIOR LOCATION
STOP INTERFERING, ACT IMMEDIATELY
CONSEQUENCES EXIST FOR INACTION
Immediately after Incident-XXXX-1A, the following transmission was received:
WE HAVE ALWAYS BEEN HERE.
