Item #: SCP-173
Object Class: Euclid
Special Containment Procedures: Item SCP-173 is to be kept in a locked container at all times. When personnel must enter SCP-173's container, no fewer than 3 may enter at any time and the door is to be relocked behind them. At all times, two persons must maintain direct eye contact with SCP-173 until all personnel have vacated and relocked the container.
Description: Moved to Site-19 1993. Origin is as of yet unknown. It is constructed from concrete and rebar with traces of Krylon brand spray paint. SCP-173 is animate and extremely hostile. The object cannot move while within a direct line of sight. Line of sight must not be broken at any time with SCP-173. Personnel assigned to enter container are instructed to alert one another before blinking. Object is reported to attack by snapping the neck at the base of the skull, or by strangulation. In the event of an attack, personnel are to observe Class 4 hazardous object containment procedures.
Personnel report sounds of scraping stone originating from within the container when no one is present inside. This is considered normal, and any change in this behaviour should be reported to the acting HMCL supervisor on duty.
The reddish brown substance on the floor is a combination of feces and blood. Origin of these materials is unknown. The enclosure must be cleaned on a bi-weekly basis.

“What the fuck are you looking at?” John Avery, presently known as D-5933, shouted at the other D-class in the cell.
“SCP-173. What the fuck are you looking at!” came the reply. This worried John, as he was staring intently at SCP-173, and the other D-class was standing behind John, facing the other direction. Then John heard the worst sound any human being had ever heard; a sneeze, coming from six inches behind his head. For a second John remembered an episode of Mythbusters he had seen before being arrested, before coming here, where they tested to see if someone could sneeze with his eyes open. He never saw the end.
There was a sick, wet thud, a horrible ripping sound, and a scream that ended too quickly. “Fu-” John managed to get out.

SCP-173 Addendum 1
On ██/██/████, SCP-173 appeared to multiply, producing two identical copies. Two D-class personnel were killed. It is unknown how this process occurred. Each instance of SCP-173, now labeled SCP-173-1 and SCP-173-2 is to be moved to individual cells each following original containment procedures.
SCP-173 Addendum 2
On ██/██/████, a second multiplication event occurred. SCP-173-1 through -4 are to be each contained as per original containment procedures. Objects reclassed as Keter.
SCP-173 Addendum 3
Security breach occurred on ██/██/████. Assuming a simple geometric progression, at least 61 copies of SCP-173 are as of now unaccounted for. It is unknown how they replicated so fast, or how they replicate at all. Video evidence of the containment breach shows multiple instances of SCP-173 working in unison across multiple cells to achieve the breach. Most of the instances still in captivity appear to have formed a 'rear guard', blocking Foundation agents from pursuing other instances. It is theorized that SCP-173 has a hive intelligence, where intelligence scales with number of nearby copies. See revised security procedures for containing SCP-173 copies.
Revised Special Containment Procedures
All copies of SCP-173 are to be contained in form-fitting metal containers and sent using SCP-███ to the now abandoned Foundation facility on the moon. They are to be fitted with tracking collars that will detect if any of them leave the moon.
SCP-173 Addendum 4
SCP-173 has caused a breach of secrecy for the SCP Foundation. Estimates at this time are roughly 500,000 civilian deaths across North America in the last 48 hours due to SCP-173, and hundreds of thousands of sightings and pieces of video evidence. Major television news programs have obtained video of SCP-173, and are providing instructions for avoiding instant death. Dr. Phillips Mathews Clef Gears Kondraki Bright is in charge of the containment.
SCP-173 Addendum 5
SCP-173 has besieged and destroyed 4 Foundation facilities near simultaneously in the last 24 hours. Each instance shows the characteristic strength exhibited in the original, and thousands working in unison are capable of ripping open concrete bunkers and compromising foot-thick steel doors. Research is ongoing to find a way to combat this threat.
Personal Log of Dr. Bright
Date: ██/██/████
I've been killed thirty-seven times in the last week. They can smell me, somehow, regardless of what body I'm in. The majority decision of the remaining O5s is that this is an XK, and they're gonna deal with the problem, or the Russians are. They're evacuating this base, which means there won't be a single Foundation scientist anywhere in the New World. They say they're gonna try to evacuate the surviving civilians, but I doubt it. There can't be more than a couple hundred people in all of North America.
The only good news is that about 150 of the bastards teamed up and ripped SCP-682 apart. Brought a smile to my face.
Revised Special Containment Procedures
Containment Zone X1, formerly North and South America, is to be denied access. Following saturation nuclear bombing on ██/██/████, number of SCP-173 instances has been reduced. All available Foundation resources are to be redirected to monitoring the ocean, to ensure the integrity of Containment Zone X1. Foundation Adjuncts from national navies are to perform around the clock patrols and sonar sweeps. Detected instances are to be contained and removed to SCP-███ for transport to the lunar containment site.
SCP-173 Addendum 6
Verified sighting of SCP-173 in ████, Wales, The United Kingdom. Nuclear bombardment authorized and executed. No survivors.