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Item #: SCP-3743
Object Class: Keter Euclid
Special Containment Procedures: The entrance to SCP-3743 is to be disguised as a private mining operation, with no less than two (2) armed guards stationed in guardhouses on either end of the opening to SCP-3743, with another ten (10) guards posing as miners around SCP-3743.
A perimeter fence stationed one mile from the entrance is to be checked bimonthly for any compromise or rusting, with a CCTV camera placed every 100 yards, with feed being run directly to each guardhouse. Any non-Foundation personnel who attempt to gain access to the site are to be detained, questioned, and then either administered Class C amnesiatics, or converted to Class D and moved to a nearby Foundation Site, based on how much knowledge the detained person(s) have of SCP-3743.
In the event that any instances of SCP-3743-C are seen within 100 yards of the entrance to SCP-3743, an alert will be called and every guard in the immediate area are to head at once to the entrance and prepare for a potential breach. Should any instances of SCP-3743-C attempt to escape, they are to be terminated and their bodies incinerated on site, and the alarmed state is to remain active until no instances of SCP-3743-C are seen for a consecutive period of four (4) hours.
Description: SCP-3743 is a subterranean cave system of unknown size and scope, of which the only entrance is a 25 yard wide, 35 yard high cave entrance along the side of Mount █████████████ █████ in Russia. As of ██-1-2018, the system appears to head at least 21 miles underground, with many other unexplored regions possibly going much deeper into the mantle of the earth. SCP-3743 has been found to harbor many species of fungi and flora not yet discovered by humanity, and study into the nature of each species has been halted indefinitely.
Current equipment and exploration is not adequate to properly estimate the full size of the tunnels, but there is common belief that the tunnels could possibly stretch across the entirety of the Pacific Ocean, and even to the Americas, if not all the way across the world.
First discovered by foundation personnel attempting to relocate an instance of SCP-3199 which had escaped from containment at a nearby facility and fled into the mountains, the initial cave entrance was found to head down at an angle of nearly 60o for 4 miles, ending in a large, open cave that extended far beyond visual sight. This first cave is illuminated by gigantic fungi hanging from the ceiling of the cave, which provide a soft blue light reaching down an estimated 300 yards from the ceiling to the cave floor. The location was noted by agents at the time and then explored in more depth once approval was given.
Upon exploration of the third large cave in the system by the second exploration team, foundation personnel found that this cave was filled with gigantic crystals of red, blue, and green, which ranged in size from 3-300 yards in height and 0.5-200 yards in diameter, now designated SCP-3743-A. Each crystal, while not immediately considered anomalous, upon further research was found to be potentially useful as energy storage, able to trap nearly 15x the energy per volume as the most advanced batteries available to humanity. However, possible extraction, further research, and use of said crystals quickly became nearly impossible as of █-█-2016, when the fourth exploration team was sent to continue mapping out the system.
As the fourth exploration team was exploring deeper into the cave system, at the 12th mapped large cave, approximately 18 miles into the crust, they discovered that this cave was filled with what appeared to be large, cylinder shaped buildings that reached from cave floor to ceiling, and were made of an unknown rock. Upon examining the interior of each building, they were found to contain anywhere between 20-100 smaller cylinders made of a dark black crystalline substance not unlike the crystals found in cave 3
As one of these crystals were being examined, one explorer happened to back into what was described as a "control panel", which began to emit a high pitched sound and vibrate the entire building. After 20-25 seconds, each crystal cylinder began to crack open, and strange beings, now designated SCP-3743-B and SCP-3743-C, emerged. When the first instance of SCP-3743-C noticed one of the exploration team, it proceeded to ███ █████ ███ █████ and ██████ ███, and it is reported that his body was then taken by an instance of SCP-3743-B and [REDACTED]. This process was then repeated with each other member of the exploration team, excluding the two members who survived.
Instances of SCP-3743-B are roughly the same height and weight as humans, but have much longer and thinner arms and legs, with a very small torso and head. They seem to lack eyes and noses, with the majority of their heads being covered by their mouths and ears. They are, for the most part, docile and have not been seen near the entrance to SCP-3743. It is assumed they are a subservient species to SCP-3743-C, which has been hypothesized to use them as menial labor and slaved.
Instances of SCP-3743-C are noticeably taller and thinner than humans, with the largest seen measuring at 7 feet 5 inches tall. They have similar anatomy to instances of SCP-3743-B, but are hostile to all human life and much more dexterous and nimble, able to move at speeds upwards of ██ mph, and lunging over ██ yards in a single bound.
Both instances of SCP-3743-B and C are hypothesized to use a combination of echolocation and detecting vibrations around them to maneuver, as the two surviving members of exploration team four were able to escape by being perfectly quiet and nor moving when any instances of SCP-3743-C were near, moving slowly and carefully with their shoes off and any clunky equipment left behind.
