SCP-3991
Item #: SCP-3991

Object Class: Safe

Special Containment Procedures: All access to SCP-3991 is restricted to personnel with Level 3/3991 clearance. Unauthorized attempts to revert this document to rev. 1 will be logged and denied - authorization to perform such procedure should be requested according to standard experiment protocols.

All personnel assigned clearance to this document should cooperate with RAISA staff in order to further advance all investigative efforts currently ongoing.

Description: SCP-3991 is the formal designation given to the first revision of this database entry. No known data exists documenting the insertion of SCP-3991 on mainstream Foundation databases; authorship, date of submission, terminal identification as well as all other information normally logged automatically during the submission of files pertaining to special containment procedures does not exist, nor appears to have ever existed according to the document's metadata.

The identification of SCP-3991's source is currently a Priority Aleph investigation subject under RAISA. Within the constraints of the Aleph designation, the following topics should be prioritized in descending order of importance:

Investigation should, first and foremost, ascertain the integrity of mainstream Foundation databases, ruling out all possibility of security breach before further research may be pursued. If such a breach is confirmed to have occurred, Protocol Occam I through -IV are to be considered enacted and thus [REDACTED].
Once outside interference has been ruled out, RAISA personnel should inform and subsequently cooperate with MTF Alpha-1, which will redirect investigation efforts towards main Foundation substructures.
The intended purpose of SCP-3991 as well as the confirmation of whether or not the anomaly described by it exists or existed at any point should be ascertained afterwards, regardless of the degree of conclusiveness achieved during investigation on aforementioned topics.
Despite the formulaic similarities to a standard SCP document, SCP-3991 advocates several containment practices not employed commonly by the Foundation. Investigative procedures conducted so far have led to postulation of several theories that may explain such disparity but no solid evidence that may ratify them has yet been uncovered.

The deletion of this document is prohibited as of ██/██/████, and all requests concerning the subject should conform to standard protocols pertaining to decommission of anomalies under the SCP designation.

◀ USER HAS VALID CLEARANCE
Item #: SCP-3991
Object Class: Thaumiel

Special Containment Procedures: SCP-3991 should be kept at special containment cell 3991-A, a 10m X 10m X 10m titanium enclosure furnished with whichever commodity and entertainment items the entity requests. SCP-3991 may exit its cell if accompanied by at least two security personnel and is granted Level 1 security credentials. SCP-3991 may not leave the premises of Site-19 under any circumstances.

Description: SCP-3991 is a humanoid Class III Essokinetic entity that resembles a non-anomalous human being of Caucasian ancestry, male gender and apparent age between twenty to thirty years of age. SCP-3991 dislikes its formal designation and has expressed desire to be referred to as "Mark Neil" - personnel interacting with SCP-3991 is advised to comply with such requests in order to avoid angering the subject.

Despite its enormous destructive capabilities, SCP-3991 has actively cooperated with Foundation personnel since containment was established. In order to encourage the maintenance of such behavior, SCP-3991 has been granted several of the aforementioned amenities.

Following Incident 3991/████, in which SCP-3991 played a key role by greatly assisting re-containment personnel engaging several Keter anomalies, it has been suggested that the entity be granted Foundation personnel status and instated as a permanent member of MTF Tau-5.

Addendum: SCP-3991 should never come in contact with any component of SCP-076, for whom the entity has expressed great aversion.

Addendum 01, ██/██/████: RAISA received multiple alerts concerning unauthorized edits to official SCP documentation. Inspection of these edits uncovered that approximately ██% of all main list files had been rewritten to resemble SCP-3991: Although the description of these documents had remained essentially unadulterated, several additions were made, including unnecessary restrictions on containment unit size, cross-containment techniques involving SCP-148, provision of containment-threatening amenities to humanoid anomalies, among others.

Efforts to revert these edits were met with preliminary failure: Although the phenomenon, henceforth referred to as SCP-3991-1, does not appear to extend outside main documentation slots, including written media and backup/archival files, all entries effected by it exhibit total expungement of their metadata. Furthermore, procedures such as revision reversion, deletion followed by insertion of archival copy and hardware replacement failed to permanently restore files affected by SCP-3991-1; unspecified software errors and immediate corruption by SCP-3991-1 were identified as the main factors behind such fact.

As of ██/██/████, SCP-3991-1 effects any documentation submitted to the main list of anomalies under the SCP designation. Means to counteract SCP-3991-1 are under discussion. Backup of archival copies have been distributed to most Foundation facilities, where temporary data-centers were installed. New SCP documents should still be sent to the main list to facilitate further study of SCP-3991-1's effects.

◀ USER HAS VALID CLEARANCE
As of ██/██/████, it has been ascertained that multiple anomalies associated with SCP-3991-1 effected documentation have ceased to exist. This phenomenon is classified as SCP-3991-1A.

SCP-3991-1A appears to primarily effect recently discovered and, consequently, documented anomalies. Once a legitimate SCP entry has been submitted to the main list within mainstream Foundation databases, it will shortly after become effected by SCP-3991-1. After at least 48 hours elapse since this occurrence, the correspondent anomaly to which the document refers to will completely disappear.

This effect is postulated to be contextually anomalous and unrestricted in scope. Anomalies pertaining to living organisms, locations, inanimate objects, celestial bodies and [DATA EXPUNGED] have been observed to vanish completely, leaving no traces nor means to confirm their existence.

Although the effects of SCP-3991-1A are most prevalent among recent entries/anomalies, it has been observed to act within the entire spectrum of SCP designations currently in use. A pattern connecting effected entries/anomalies has yet to be identified.
It is currently unknown if SCP-3991-1A can be counteracted and if such course of action is indeed desirable.