Per 
SCP-XXXX
Item #: SCP-XXXX
Object Class: Safe
Special Containment Procedures: SCP-XXXX is to remain in Vault-12, and should not be entered without approval from the current site director.
Description: SCP-XXXX is a wooden door. Upon stepping through SCP-XXXX, an individual becomes superposed between an unknown amount of realities. Said individual will remain in this state until someone checks which reality they are in, destroying the other realities in the process.
A better explanation of this anomalous effect can be seen in the "Schrodinger Cat" thought experiment. If a cat is in a box, an outside observer would be unable to know if said cat was dead or alive without opening the box. As such, until the box is opened the cat is both dead and alive. This special state of being collapses upon opening the box, wherein the cat is either dead or alive.
Similar to how the cat can be both dead and alive, subjects who enter SCP-XXXX exist in multiple realities at once. Furthermore, like said cat, a subject inside of SCP-XXXX will only exist in one of those realities when someone checks their location. This can occur by communicating with said individual, or by reading transcripts of past conversations.
Addendum 1:
The following is an experiment log recorded by Junior Researcher Grey. It should be noted that this experiment was originally supposed to be performed by Dr. ███████, while Ms. Grey observed and helped when necessary. However, due to a last minute familial issue, Dr. ███████ was unable to perform this experiment, and authorized Ms. Grey to perform it in his place.
Note from Dr. Grey:
I am so excited! My first SCP! I cant wait!
Date: September 8, 20██
Time: 6:38 PM
Procedure:
D-3903 was given a portable communication device, and was instructed to enter SCP-XXXX. Below is a recorded transcript of said device.
D-3903: There are several pyramids in the distance. The sky is purple and the sand is green.
Dr. Grey: I really am sorry about… Well, about everything.
D-3903: It doesn't matter. I was gonna die either way.
Dr. Grey: Look, I dislike the termination policy, but I have-
D-3903: Can you do a dead man a favor?
Dr. Grey sighs
Dr. Grey: Sure.
D-3903: Can you please listen to my story? You're the last person I have a chance to convince that I'm not crazy. My mom died when I was about 3 months old. She was killed, by my father. Drowned in the bathtub of their new home.
D-3903: I was then sent to live with my Grandmother. She died when I was 7. I don't remember much of the following few years. It's as if there is a cloth covering my memories. The first thing I can clearly recall was when I was 12, and I was exiting a doctor's office after getting vaccinated for the flu.
D-3903: From that 5 year time span I vaguely remember something happening at my old school. Some sort of animal that was captured by animal control. I recall that the creature killed multiple teachers and students. I have a vague remembrance of the feeling I felt when I was adopted. Other than those two events I don't remember much else.
D-3903: I eventually graduated high school, and got a job at a lumber mill. I managed to make a small living, eventually settling down with a gal named Rebecca. She was perfect. A few days before our marriage a creature broke into our house. It was a tall and humanoid, but instead of hands and feet it had hooves. It was so skinny that one could count how many bones the creature had, and was covered in black leathery skin. However, by far the creepiest thing about it was its face. It looked like a hybrid of a deer skull and a humans face, almost like the two were haphazardly melted together. It hurt to look directly at it.
D-3903: Despite not having hands, it somehow wielded a large black butchers knife. It must have been the length of my arm, but the only thing scarier than that creature was what it was doing. It had killed Rebecca, and was spreading her organs all over our house. I did the only thing I could think of. I grabbed my hunters gun and shot, but the bullets did nothing. If anything, they went through him. Eventually it left… although I don't know how. I blinked and it was gone. My neighbors must have heard the gunshots coming from my house and called the police.
D-3903: Everyone thinks that I killed her. Maybe their right, and I am just a madman locked in a padded cell somewhere. But I know what I saw that day, and I swear to you that it was real. I have spent every day of my life since then thinking, wondering, why did she have to die? Why couldn't it have been me?
D-3903: When I told the police what had happened, they obviously didn't believe me. I was arrested, and charged with a life sentence. Then, one day a man offered me a chance out. A chance at redemption. I took it. Now I can only hope that I see her again when I… Well, you know… Kick the bucket.
Dr. Grey: Deri- I mean, D-3903, for what it is worth, I believe your story.
D-3903: Thanks. It is nice to know that at least someone out there thinks I'm not crazy. I am almost at the base of a pyramid. I can see the outline of the door from here. I should be able to reach it in about 20 or 30 minutes.
Dr. Grey: When you enter it, be sure to tell me what you see.
D-3903: Sure thing, Doctor Grey, sure thing.
There is relative silence for the next 27 minutes
D-3903: Okay, I am at the door.
D-3903: I see a mountain... | I'm in a jungle...
