Item #: SCP-1303
Object Class: Safe
Special Containment Procedures: SCP-1303's location is to be cordoned off with a standard security fence, cameras, and no-trespassing signs at a distance of one (1) kilometer from the entrance. A team of four (4) agents should remain on duty near SCP-1303's entrance at all times in National Park Service Ranger uniforms to intercept approaching civilians and direct them away from the site. Should containment be breached and an unauthorized individual obtain access to SCP-1303, two of the four agents should enter the site on tethers and attempt to retrieve the trespasser alive. Upon successful retrieval, Class-B amnesiacs should be administered and the individual relocated to a safe distance.
Description: SCP-1303 is a linked set of eleven (11) natural caverns, located in [REDACTED], with one known surface entrance and a series of interconnecting passages. The caverns' sizes range from ten (10) meters across to approximately thirty-seven (37) meters across, reaching a maximum depth of one hundred and twenty (120) meters below ground level. The location is host to two potentially related phenomena, designated SCP-1303-1 and SCP-1303-2, that constitute the location's anomalous properties. Through the entire period of Foundation ownership of the site, SCP-1303-1 and 1303-2 have never been observed to overlap their areas of effect.
SCP-1303-1 is an intermittent effect that consists of the total absence of acoustic transmission within its area. It has been known to occur in every cavern connected to the SCP-1303 network, including the entrance cavern, though it exhibits no discernible pattern for manifestations. The phenomenon persists for a variable amount of time, ranging from five minutes to a record of four hours, and its boundaries never extend past those of the cavern it is currently affecting. Within SCP-1303-1's area, no sound waves of any sort can be generated or detected, regardless of whether they would be generated by a source inside the area travelling outward or vice versa. The effect extends to both mechanical devices and living subjects, though it is only known to manifest when a living subject is present. Affected mechanical devices exhibit all signs of perfect functionality except for their inability to transmit or detect sound waves. Personnel within SCP-1303-1's area of effect have persistently reported a sensation of being stalked or followed, catching glimpses of something moving out of the corner of their eye and a heightened urge to either flee or turn and confront whatever is there. In all such cases, electronic media and other personnel regularly fail to sense or detect the supposed 'stalkers', though multiple personnel within an affected area each experience such feelings independently. Due to dependency on minor echoes for balance and orientation, individuals who attempt to flee put themselves at high risk of injury.
SCP-1303-2 is an effect similar to SCP-1303-1, though instead of actively suppressing sound waves, the phenomenon completely inhibits any production or detection of visual, infrared, or ultraviolet light. It manifests in any of the SCP-1303 caverns except for the entrance cavern, and persists for anywhere from five minutes to over nine hours. Like SCP-1303-1, it affects both living subjects and mechanical devices without otherwise impeding their operation, and only manifests when a living subject is present, though its effects remain for a variable duration after the subject has left its area of effect. From the 'outside', the phenomenon appears to be a solid, opaque black wall, though it has no physical permanence and can be crossed freely. From the 'inside', no visual input of any kind registers, regardless of the location of the source. While inside an instance of SCP-1303-2, personnel have reported hearing, over the background noise of the cavern, noises that indicate an approaching creature or object of some kind. The exact details of the sounds vary, but in all cases exhibit traits of something or someone approaching the subject at a slow, deliberate pace, and in no instance has any such sound been registered or detected by recording equipment. As with SCP-1303-1, exposure to this effect triggers an anomalously strong fight-or-flight urge in affected subjects, which can lead to significant personal injury in the rough terrain of SCP-1303.