Per 
Item #: SCP-XXXX
Object Class: Euclid
Special Containment Procedures: Sites 1635, 1636, and 1678 have been established around structures containing known instances of SCP-XXXX-1, hereafter referred to as SCP-XXXX-1-A through SCP-XXXX-C. Each structure within these Sites is to have all entrances marked as "Condemned, do not enter". Each Site is to be guarded by Foundation agents posing as private security.
Should an additional instance of SCP-XXXX-1 be located, local Foundation agents are authorized to immediately pursue any viable means of acquiring the structure and alert Dr. Lisdrom of the newly located instance, as well as any viable means of acquisition yet found.
SCP-XXXX-1 instances are to be kept shut and locked at all times, outside of testing and/or expeditions into SCP-XXXX-2. Should any instance of SCP-XXXX-2-A escape through SCP-XXXX-1, on-site security is authorized to terminate the instances immediately.
Description: SCP-XXXX-1 refers to two three1 doors, seemingly made of cedar wood, although, they are seemingly immune to any damage, making material sampling and testing as-of-yet impossible. The doors have a standard key-locking door handle, with a key tied around the door handle with what appears to be twine. These doors appear at the top of enclosed staircases in residential homes, so far only seen outside of densely populated areas.
When opened, SCP-XXXX-1 instances lead into an extra-dimensional space hereafter referred to as SCP-XXXX-2. SCP-XXXX-2 is a seemingly endless space of non-euclidean geometry, composed mostly of staircases, landings, and doors. Some rooms and even complexes have been reported inside, but attempts to relocate these have proved as-of-yet fruitless. All doors within SCP-XXXX-2 are identical instances of SCP-XXXX-1, and, when opened, lead to what appear to be parallel realities to our own. SCP-XXXX-1 instances inside SCP-XXXX-2 are almost exclusively found locked, however, the interior side of the door can be unlocked by simply turning the door handle the counterclockwise before turning it clockwise to open it. Expeditions beyond these doors are currently under suspension, see incident report SCP-XXXX-D.
In addition to its unusual geometry, sections of the space seem to visually loop or move, even to those within SCP-XXXX-2. This can cause incredible disorientation to subjects within the space. Visually looping includes entities within the space, and, should a subject occupy a looping space, they are capable of observing their own body from an outside perspective. Prolonged exposure to the multiple reality-bending phenomenon of SCP-XXXX-2 has shown to cause individuals returned to normal space incredible issues with balance and depth perception for anywhere from a few hours, to several days.
Other subjects within SCP-XXXX-2 have reported seeing faces, skulls, and other shapes within SCP-XXXX-2's geometry, only to have said shapes disappear once the subject has moved position, replaced by constructs normal for the space. When asked to return to the space such shapes were viewed from, either the shape never re-visualizes, or is replaced by a different shape altogether.
The interior design of SCP-XXXX-2 rearranges itself, seemingly whenever unoccupied, however, further testing on this is needed to verify this. This makes mapping the interior of SCP-XXXX-2 nearly impossible. Although instances of SCP-XXXX-1 in our reality have yet to change relative position to each-other, no other instance of SCP-XXXX-1 within SCP-XXXX-2 have retained position after a rearrangement event.
It is possible for an individual to move throughout SCP-XXXX-2 with relative ease, the space seeming to grant occupants knowledge of how its internal geometry works. It is even possible to move to staircases facing any direction from oneself by leaping, although the change in gravitational direction on landing has been described as "nauseating" and "extremely uncomfortable". Recordings of the interior of SCP-XXXX-2 confer no such understanding, and, to those who were not actively inside SCP-XXXX-2 at the time of recording, are nearly unintelligible.
SCP-XXXX-2-A refers to a group of large (roughly 3 meters long) machines, similar in appearance to ants, that patrol and maintain SCP-XXXX-2. While within SCP-XXXX-2, they appear passive, observing individuals within should they venture within an approximate 20 meter space. SCP-XXXX-2-A instances have also been observed to attempt to open SCP-XXXX-1 instances. Should one be found unlocked, they will travel through it, and any other instances within line-of-sight will move to do the same. Once all SCP-XXXX-2-A have moved through the SCP-XXXX-1 instance, it will close and lock itself.
Addendum SCP-XXXX-1: On ██/██/200█, the Foundation received reports of "giant ants" attacking a small farming area in █████████, ██, United States. Upon arrival, Foundation Agents found four instances of SCP-XXXX-2-A dismantling anything mechanical they came across and bringing the resulting parts to a two-story farmhouse. SCP-XXXX-2-A instances had no interest in anything non-mechanical, unless provoked. Upon initial engagement with local law enforcement, they immediately moved to crush anything viewed as a threat between their mandibles.
After terminating the entities, Foundation Agents entered the farmhouse, which had been stripped of all exposed metal, and found no evidence of anything the SCP-XXXX-2-A instances had collected. Foundation Agents found a paper taped to the SCP-XXXX-1 instance within, noting the coordinates of the first two SCP-XXXX-1 instances. Foundation personnel moved to secure the second building it occupied, located in an abandoned home outside of ███████████, India.
Expedition logs: