Per 
Item #: SCP-4863
Object Class: Keter
Special Containment Procedures: SCP-4863 is to be kept in a 7 m x 7 m x 7 m cube composed of lead-lined steel and titanium at Site ██. The containment chamber is equipped with tesla guns with powers up to 1200 milliamperes to subdue SCP-4863-1 during the event of a breach. An airlock with 2 high voltage tesla gates is the only way inside to SCP-4863's containment chamber. A research room is located next to the containment chamber with a window made out of thick layers of bulletproof glass to observe the containment chamber. All personnel must be authorized by two (2) level 4 staff before coming in contact with SCP-4863.
The containment chamber is to be cleaned every 2 days, with constant surveillance during the cleanup. All liquid emitted from SCP-4863 is to be dumped into a remote lake north of ██████████, New Mexico. In the case of a breach, MTF squad Alpha-3 ("Bed Bugs") is to be deployed immediately to contain SCP-4863-1.
To prevent SCP-4863-1 from manifesting, every 23 hours a randomly selected D-Class will be instructed to go inside SCP-4863's containment chamber and sleep on SCP-4863. This is done most commonly during the late evening. At least 4 guards and 2 researchers should be present at this time. MTF Alpha-3 is on standby at this time. If the D-Class refuses to sleep, a sleeping gas (Halothane) will be released into the chamber. If all goes successfully, after waking up the D-Class is immediately put into drug-induced amnesia. If the mission is unsuccessful and SCP-4863-1 gets loose, the tesla guns in the containment chamber should immediately be used on SCP-4863-1 to subdue it. All researchers present must evacuate. If SCP-4863-1 gets past the airlock, a full site lockdown needs to be initiated immediately. MTF Alpha-3 should be deployed to contain SCP-4863-1.
Description: SCP-4863 is a standard size twin bed, colored dark grey. It is manufactured by ██████. It is composed of the standard materials for beds, but the mattress is impossible to be separated from the frame of the bed. SCP-4863 is seemingly indestructible, with nothing being able to tear, shatter or crack it. SCP-4863 constantly leaks a highly corrosive liquid from its feet. The liquid is described as thick, dark and with a strong scent of burning plastic.
The true anomalous properties of SCP-4863 are activated once a human being falls asleep while laying on it. The person who sleeps on SCP-4863 will seemingly sink into the mattress and frame of the bed. Any attempts to either wake or pull the person away from SCP-4863 have failed. Viewing the process with heat cameras have shown the person fading away once he/she has sunken into SCP-4863. SCP-4863 leaks excess amounts of the corrosive liquid during this process.
Once completely submerged, the person will wake up in a different dimension. This dimension is referred to as SCP-4863-B. SCP-4863-B is described as being a seemingly endless hallway, with a floor made out of 30cm x 30cm white ceramic tiles and walls made out of red bricks. The width of the hallway is 1.7 m. The height of the roof is unknown, and it seems to be just as long as the hallway itself. The hallway is dimly lit by light bulbs with protective mesh fencing attached to the walls.
Subjects inside of SCP-4863-B report feelings of queasiness and nausea. Explorations of SCP-4863-B have reported at least 223 metal doors. These metal doors all lead to different spaces. Some lead to other hallways. some to rooms and some have nothing behind them except a wall [See Addendum: SCP-4863-B-1 for descriptions of the spaces found in SCP-4863-B]
Inside SCP-4863-B exists also another entity, referred to as SCP-4863-1. SCP-4863-1 is described as a humanoid entity, approximately 2.5 meters in height. It is colored pitch black, the color works as a camouflage in the dark hallways of SCP-4863-B. It has unnaturally long arms and legs, both measuring 1.5 meters long. Its arms and legs have long fingers and toes with sharp and long nails for climbing and harming prey. Even though it is humanoid, it is not bipedal. It is a quadruped and can climb very well. It has inhuman reflexes, being able to react in 0.0001 seconds. It is also fast, reaching top speeds of 80 km/h.
SCP-4863-1 in its natural habitat often hides high up in the hallway, where it cannot be seen without special equipment. When SCP-4863-1 spots prey in its natural habitat, it stalks the prey from high above, frequently vocalizing to induce anxiety in its prey. After about 2 hours of stalking, it drops down on its prey and kills it with either a cutthroat or blunt force trauma. It is not certain, but it is speculated that SCP-4863-1 consumes its prey.
When a person enters SCP-4863-B, a sort of timer is put on. If the person survives for 3 hours inside SCP-4863-B, said person will start feeling dizzy and light-headed, causing them to collapse. They will then remerge out of SCP-4863. Any wounds or damage the person suffered inside of SCP-4863-B stays. Often the person is not in critical condition, but therapy is often needed to treat mental damage like post-traumatic stress disorder (PTSD).
If the person is killed inside of SCP-4863-B by SCP-4863-1, instead of the person that went into SCP-4863 remerging, SCP-4863-1 will emerge instead. The containment procedures for an SCP-4863-1 breach should be immediately followed. SCP-4863-1 is difficult to contain caused by the fact that SCP-4863-1 cannot be killed. Bullets and other harmful objects seem to harm it, but they can't kill it. Electricity seems to be an effective option against SCP-4863-1, being able to subdue it for an effective period. SCP-4863-1 can return to SCP-4863-B at any time at will by fading away. The exact causes for it retreating to SCP-4863-B are unknown since it can take a lot of damage and not escape, but it can take minimal damage and still escape. This makes a breach dangerous since it is unpredictable.
Addendum: SCP-4863-B-1
The following is a list of exceptional spaces found inside SCP-4863-B.
Space #2: A 5 m x 5 m x 5 m x room, made entirely of copper. A single standard yellow rubber duck is laying in the middle of the room.
Space #7: A 3 m x 3 m x 3 m room, with colorful walls and floor. A table with a sponge cake topped with icing reading "He is above you" is placed in the back of the room. A clown doll measuring 1.5 meters in height is standing in the lower-left corner of the room.
Space #9: A sphere-shaped room, 5 meters in diameter. Composed entirely out of sulfur crystals. The room has zero gravity.
Space # 13: A 8 m x 8 m x 8 m room, with wooden floorboards and blue walls. A man, approximately in his 30s and 1.8 meters tall with a grey two-piece suit, sits in the middle of the room on a rocking chair. He is reading a newspaper. He is reported as saying: "You know, it is a twisted world we live in. Or that you live in. I live in this goddamn mess. Can't get a second of silence for myself. I was like you once. I think I was the first one to sleep in this bed. He killed me. You're probably going to die too. If you explore deep enough, you'll find the rest of all the poor souls that are trapped in this place. Trust me, you don't want to live down here. Now go, you're not safe in this room."
The man was unresponsive to any questions asked.[DATA CORRUPTED]
Addendum: Incident 4863-A
Incident 4863-A is the name given to the chain of events that took place on 7/4/19██. The events started at 9 AM.
9 AM
SCP-4863 is brought into Site ██. The only anomalous effect was thought to be the corrosive liquid that leaks from SCP-4863. SCP-4863 is initially classified as safe and put into a standard containment unit with a metal floor.
1 PM
A level 3 staff member is on his lunch break and decides that he wants to take a nap. The staff member walks into the containment unit and sees SCP-4863. He mistakes it for a normal bed and takes a rest in it. He sinks into SCP-4863 and enters SCP-4863-B.
3 PM
The level 3 staff member is presumably killed by SCP-4863-1. SCP-4863-1 emerges out of SCP-4863. SCP-4863-1 quickly breaches containment. The light containment zone is quickly locked down after SCP-4863-1 has killed 10 staff members. All staff are now essentially trapped inside of the light containment zone.
4 PM
SCP-4863-1 has now killed all 2██ staff inside of the light containment zone. A report of 3█ SCPs have been neutralized by SCP-4863-1. The facility is evacuated and MTF Epsilon-11 ("Nine-Tailed Fox") is deployed to contain SCP-4863-1.
5 PM
MTF Epsilon-11 ("Nine-Tailed Fox") has now successfully contained SCP-4863-1. SCP-4863 is immediately moved into a new containment chamber in the heavy containment zone. SCP-4863 is given Keter classification. The light containment zone of Site ██ is completely destroyed. Work in the heavy containment zone is continued as usual. The light containment zone is put under renovation.
Aftermath Of The Incident
The foundation lost 3█ anomalies and many high-value staff were KIA. All work had to be halted in the light containment zone, damaging the foundations ability to contain more anomalies. An estimated █ anomalies escaped during Incident 4863-A. Only █ anomalies were contained.
