Per 
Item #: SCP-XXXX
Object Class: Safe
Special Containment Procedures: As SCP-XXXX-1 is immobile by any means less extreme than demolition of the surrounding structure, it is to be preserved as discovered in the building now under the operation of the Foundation front group "Shelly & Clarke Pharmaceuticals". The hallway housing SCP-XXXX-1 is to be guarded by a light security detail at all hours. SCP-XXXX-1 is to have the following measures to prohibit unauthorized access: a magnetic lock opened by the identification badges of personnel with Clearance 3/XXXX or above, and an electronic combination lock with a six-digit password rotated weekly by on-site Clearance 4 personnel.
Access to SCP-XXXX is prohibited without authorization from personnel with Clearance 4/XXXX. If instances of SCP-XXXX-3 are to be interacted with, a log of the intended procedure must be submitted to the containment site's head researcher for approval. Only one biological or one advanced mechanical entity may be present in SCP-XXXX-2 at any given time (see Addendum). Personnel may keep in contact with entities entering SCP-XXXX-2 using standard electronic audiovisual communication. Under no circumstances are any instances of SCP-XXXX-3 to be removed from SCP-XXXX-2.
Description: SCP-XXXX is an anomalous enclosed space discovered on ██/██/19██, contained within an abandoned two-story building of early 20th-century architectural design at ██████████. Anomalous properties were first reported by local law enforcement investigating the disappearance of ████ K██████. The Foundation purchased the surrounding property and renovated the structure to have the appearance of of a pharmaceutical research center.
An un-embellished oak door approximately 2 meters high with a brass handle, hereby referred to as SCP-XXXX-1, is located within a first floor hallway of the facility. The original brick wall holding SCP-XXXX-1 has been preserved and covered with the material used in the construction of the rest of the facility's material. All means of attempting to bypass SCP-XXXX-1 and view the interior of the anomaly show an unlit empty space completely surrounded by the walls and ceiling of the facility, geometrically consistent with the overall structure of the facility and showing no anomalous properties.
Opening SCP-XXXX-1 will reveal a completely dark space on the other side. No light source used from outside of SCP-XXXX has been capable of illuminating the space, and electromagnetic radiation seems to be absorbed or otherwise not reflected by any apparent bounds. When a biological entity an entity showing any discernible degree of sentience crosses the threshold of SCP-XXXX-1, they will find solid ground to stand on, despite said feature not being detectable by any form of radiation from outside, and upon closing the door, the darkness will remain for approximately ten seconds. During this timeframe those who have entered the anomaly report a feeling of "being watched", and monitoring devices have confirmed an unknown impulse travelling through the periphery nervous system of the entrant that leads to brief contraction of most skeletal muscles beginning at the occipitofrontalis in the forehead and ending at the lumbricales in the feet. After this period, the illumination in the anomaly increases to show a wooden room with a mahogany writing desk, an accompanying leather-bound office chair, an inkwell with various quills, and masses of bookshelves that stretch beyond visible sight. No light sources are detectable within this space (hereafter referred to as SCP-XXXX-2), but there is continuous ambient lighting reminiscent of lantern light or a shaded fireplace.
Upon the bookshelves in SCP-XXXX-2 are a collection of hardcover books of various colors, hereby referred to as SCP-XXXX-3. SCP-XXXX-3 appear to be arranged by the form of divisional tiers labeled in gold print upon the spines, with the most prominent mark being Roman numerology from I (one) to XXIII (twenty-three). Beneath these markings are a subcategorization of the numerals 1 or 2, except in the case of those instances of SCP-XXXX-3 marked with XXIII, in which they are instead classified as either X or Y. The information within these books conforms with the genetic composition of biological entities who have entered SCP-XXXX-2, recording in columnar print strings of the capitalized letters A, C, G, and T. No precise number has been recorded for the standard number of instances of SCP-XXXX-3 within SCP-XXXX-2, but measurements taken of the anomaly's dimensions give an approximate value of 50,000, although clear outliers have been observed under certain circumstances (see Experiment Log XXXX-XX).
