The Threshold Protocol

Item #: SCPG-029

Object Class: Keter

Special Containment Procedures: SCPG-029 is to be contained within a specialized containment chamber at Site-██, designated Containment Unit-4729-Alpha. The chamber consists of a primary containment cell measuring 15m x 15m x 8m, constructed with reinforced concrete walls embedded with a Faraday cage mesh and lined with SCP-148 ("Telekill") alloy plating. The chamber is to be maintained at a constant temperature of 4°C ± 0.5°C and relative humidity of 30% ± 2%.

A secondary containment perimeter extends 50 meters in all directions from the primary chamber, equipped with motion sensors, thermal imaging cameras, and Class-VII reality anchors positioned at 10-meter intervals. No fewer than twelve (12) armed security personnel are to maintain watch at all times, with shifts rotating every four hours. All personnel assigned to SCPG-029 must undergo weekly psychological evaluation and monthly amnestic treatment to prevent long-term exposure effects.

SCPG-029 is to be monitored continuously via closed-circuit cameras equipped with automated anomaly detection software. In the event of dimensional aperture manifestation, Protocol Threshold-Seven is to be initiated immediately:

All personnel within 100 meters of SCPG-029 are to evacuate to designated safe zones
Automated containment systems will deploy aerosol sedatives and electromagnetic pulse charges
Mobile Task Force Mu-13 ("Ghostbusters") is to be notified and deployed within 15 minutes
Site Director authorization is required for any personnel to approach within 50 meters of an active aperture

Under no circumstances are personnel to make physical contact with SCPG-029 during an active phase. Any individual who enters an aperture generated by SCPG-029 is to be considered lost and presumed KIA after 72 hours, unless otherwise specified by O5 Command.

Description: SCPG-029 is an irregularly-shaped metallic archway measuring approximately 3.2 meters in height and 2.1 meters in width. The object appears to be constructed from an unknown alloy exhibiting properties inconsistent with any known terrestrial materials. Spectroscopic analysis has revealed the presence of elements not found on the periodic table, designated SCPG-029-A through SCPG-029-F. The archway's surface displays intricate geometric patterns that appear to shift and reconfigure when observed directly, causing mild disorientation and headaches in viewers after prolonged exposure.

SCPG-029 exhibits three distinct operational phases:

Dormant Phase: SCPG-029 appears as a simple archway with no anomalous activity beyond the shifting surface patterns. This phase typically lasts between 72-168 hours. During dormancy, the object maintains a constant temperature of 12°C regardless of ambient conditions and emits low-level electromagnetic radiation in the 40-60 Hz range.

Activation Phase: Characterized by the manifestation of a translucent, shimmering membrane within the archway's frame. This membrane exhibits properties consistent with a dimensional barrier or "doorway" to alternate realities. The activation phase is preceded by a 15-30 minute warning period during which SCPG-029 emits increasingly intense electromagnetic pulses and audible humming at frequencies ranging from 20-200 Hz. Surface temperature increases to approximately 45°C during this phase.

Active Phase: The membrane becomes fully opaque and stable, allowing bidirectional travel between our reality and the connected dimension. Active phases last between 30 minutes and 6 hours, with an average duration of 2.3 hours. During this phase, SCPG-029 has been observed to connect to no fewer than ██ distinct alternate dimensions, designated SCPG-029-1 through SCPG-029-██.

The dimensional destinations appear to follow no discernible pattern, ranging from apparently benign alternate versions of Earth to hostile environments populated by dangerous entities. Of particular concern are connections to dimensions designated SCPG-029-7, SCPG-029-12, and SCPG-029-23, which have resulted in multiple containment breaches and casualties.

Dimensional Survey Summary:

SCPG-029-1: An Earth-like dimension where human civilization appears to have developed along similar lines to our own, with minor historical variations. No apparent hostile entities encountered.

SCPG-029-3: A dimension consisting entirely of an endless ocean under a starless sky. Water samples reveal normal H2O composition but with trace amounts of SCPG-029-A element.

SCPG-029-7: [DATA EXPUNGED] - See Incident Report 4729-Alpha

SCPG-029-12: A dimension populated by entities resembling large arthropods with apparent sapience. These entities, designated SCPG-029-12-A, have demonstrated aggressive behavior toward human subjects and possess natural weaponry capable of penetrating Level IIIA body armor.

SCPG-029-15: A dimension where the laws of physics appear fundamentally altered. Gravity operates in random directions, and electromagnetic radiation behaves as a liquid substance. Extended exposure causes severe neurological damage in human subjects.

SCPG-029-23: [REDACTED BY ORDER OF O5-COMMAND] - See Addendum 4729-C

Discovery: SCPG-029 was discovered on ██/██/20██ in the basement of an abandoned research facility in ████████, New Mexico, following reports of "strange lights and sounds" from local residents. The facility was later identified as belonging to Dr. Marcus Holloway, a theoretical physicist who had been researching dimensional mechanics under a classified government contract. Dr. Holloway was found deceased in the facility, apparently having been [DATA EXPUNGED]. His research notes, partially recovered and heavily damaged, suggest that SCPG-029 was constructed as part of Project ████████, a military application of dimensional travel technology.

Addendum 4729-A: Incident Report 4729-Alpha

Date: ██/██/20██ Incident Classification: Level 4 Containment Breach Reporting Officer: Dr. Sarah Chen, Site-██ Research Director

At 14:32 hours, SCPG-029 entered an unexpected activation phase approximately 18 hours ahead of predicted schedule. The connected dimension was later designated SCPG-029-7. Unlike previous dimensional connections, SCPG-029-7 exhibited immediate signs of hostile activity.

At 14:47 hours, multiple entities emerged from the aperture. These entities, designated SCPG-029-7-A, appeared as humanoid figures approximately 2.5 meters in height, composed of what can only be described as "living shadow." The entities demonstrated the ability to phase through solid matter and exhibited extreme hostility toward all human personnel.

Security response was hampered by the entities' incorporeal nature. Conventional weapons proved ineffective, and the entities began systematically hunting personnel throughout the facility. At 15:12 hours, Dr. ████████ was found deceased in Laboratory-7, with his body showing signs of rapid cellular decay consistent with extreme cold exposure, despite the absence of any temperature change in the environment.

At 15:28 hours, Researcher Johnson discovered that high-intensity UV lighting caused the entities to retreat. Emergency UV floodlights were activated throughout the facility, forcing the entities back toward SCPG-029. The aperture closed at 16:04 hours, trapping three entities on our side of the dimensional barrier.

The trapped entities became increasingly agitated and began emitting subsonic frequencies that caused severe disorientation in nearby personnel. Mobile Task Force Mu-13 successfully contained the entities using portable UV projectors and specialized containment units lined with mirrors to maintain constant light exposure.

Casualties: 3 KIA, 7 injured, 2 requiring psychological treatment Status: Containment protocols updated to include UV lighting systems and early warning sensors

Addendum 4729-B: Research Note - Dr. Elizabeth Vance

Date: ██/██/20██

After extensive analysis of the electromagnetic patterns emitted by SCPG-029 during activation phases, I believe I have identified a potential method for predicting which dimension the object will connect to. The frequency modulations appear to correspond to specific dimensional "signatures," much like radio frequencies correspond to different stations.

If my hypothesis is correct, it may be possible to develop technology that could influence or even control SCPG-029's dimensional targeting. However, I must stress that any such experimentation carries extreme risks. The object's connection to hostile dimensions like SCPG-029-7 and SCPG-029-23 suggests that some realities are inherently dangerous to our own.

I am requesting permission to begin controlled experiments using modified radio transmission equipment to attempt communication with SCPG-029 during its dormant phases. If successful, this could represent a breakthrough in our understanding of dimensional mechanics.

Request Status: DENIED by Site Director - Risk assessment deemed unacceptable

Addendum 4729-C: O5 Classification Notice

Date: ██/██/20██ Classification Level: O5 EYES ONLY

Following the events of ██/██/20██, all information regarding SCPG-029-23 has been classified at the highest level. The dimension connected during Event 4729-Omega represents a potential XK-Class End-of-World scenario if a stable connection were to be established.

SCPG-029-23 appears to be inhabited by entities that demonstrate not only extreme hostility toward human life but also the apparent ability to "infect" our reality with their presence. The single entity that emerged during the 47-second connection was responsible for the complete destruction of Testing Chamber-B and the loss of an entire research team before being neutralized.

Of greater concern is the entity's apparent ability to communicate with SCPG-029 itself. Electromagnetic monitoring detected complex signal exchanges between the entity and the archway, suggesting a level of intelligence and technological capability that far exceeds our current understanding.

Any future connections to SCPG-029-23 are to be met with immediate deployment of nuclear failsafe protocols. Site-██ has been equipped with a 50-kiloton warhead specifically for this contingency, with detonation authorization delegated to the Site Director in the event of O5 Command communication failure.

Additional containment note: Recent analysis suggests that SCPG-029's activation frequency is increasing. What began as monthly cycles have accelerated to bi-weekly, then weekly occurrences. If this pattern continues, SCPG-029 may eventually reach a state of permanent activation, making containment impossible with current protocols.

Research into permanent neutralization methods is ongoing, though all attempts thus far have proven unsuccessful. The object appears to be constructed from materials that exist partially outside our dimensional space, making conventional destruction techniques ineffective.

Current Threat Assessment: CRITICAL - Potential for XK-Class End-of-World Scenario if containment fails

Recommended Action: Continued monitoring and research into neutralization methods. Preparation for potential relocation to off-world containment facility pending approval of Project ████████.

Final Note: SCPG-029 represents one of the most significant threats currently contained by the Foundation. The object's unpredictable nature, combined with its connections to hostile dimensions, makes it a constant source of potential catastrophe. All personnel assigned to SCPG-029 are reminded that the safety of our reality may depend on maintaining its containment.

The Threshold Protocol remains our primary defense against the unknown dangers that lie beyond the boundaries of our dimension. Failure is not an option.