Per 
Special Containment Procedures: SCP-XXXX is deceased as of August 3 2019. Along with its expiry was the ceasing of anomalous properties. The corpse of SCP-XXXX is to remain in a preservation tank inside a standard containment locker.
Description: SCP-XXXX was a Betta splendens (Siamese fighting fish), that displayed no remarkable characteristics apart from its abnormally long and thin tail. SCP-XXXX-1 was an unknown location accessed via feeding SCP-XXXX. SCP-XXXX-1 was a large open space with clusters of rooms, with the "sky", floors, and walls, being a solid marmalade coloured material.
If a subject proceeded to enter one of the rooms within SCP-XXXX-1, an elderly man would materialize and begin to speak. The area around the subject would change rapidly to fit the room's "theme". The being was deemed SCP-XXXX-2. Once SCP-XXXX-2 was activated, the world around the subject would morph into one of (choose how many) "sets" that varied from a simple field to forests constructed out of mirrors.
SCP-XXXX-1 Exploration Logs:
Exploration Log 1
Date: 2/4 2017
Exploration Team: D-356, charged with 30 accounts of 1st-degree murder, rendered mute via the self-mutilation of vocal cords
Subject: SCP-XXXX-1
Equipment: A shoulder-mounted video camera.
Aim: Gain a rudimentary understanding of SCP-XXXX-1
[BEGIN LOG]
D-356 enters SCP-XXXX-1 without complications. They show initial confusion and pull out their debrief notice. D-356 wanders around for several minutes before opening one of the many doors, leading to a vast black space. A voice hereby referred to as SCP-XXXX-2, emanates from around the entirety of the space.
SCP-XXXX-2: "Six hundred and thirty-one days… Welcome, sister."
A sun rises in the distance, the ground morphing into a field and sprouting flowers as hills rise with the sun. This process continues for 30 seconds before coming to an abrupt stop. D-356 shows no signs of distress, but is visibly confused and runs their hand along the grass. A man (SCP-XXXX-2) looking between the ages of 60-75 materializes along with a stump next to D-356. SCP-XXXX-2 sits down and snaps his fingers, causing a three-piece suit typical of that worn in the 1920s to replace his tank top and jeans. They proceed to pull a bottle of whisky from one of the suit pockets along with two ice-filled glasses.
SCP-XXXX-2: "Don't leave an old man hanging, have some." UN pours a glass and hands it to D-356, they accept and UN pours themselves a glass. "It's been a while, hasn't it?" UN smiles awkwardly, fumbling with an object within his pocket. "You're probably confused, scared maybe, here." UN hands D-356 a chunk of concrete with the date 12/12/2016 inscribed. "I'm not just gonna tell you everything on the spot, but you already knew that."
D-356 is thrown out of the room by a gust of intense wind and subsequently expelled from SCP-XXXX-1, materializing back where they had initially been standing prior to feeding SCP-XXXX.
[END LOG]
Notes: analysis of the piece of concrete given to D-356 reveals no anomalous properties. No events barring significant correlation to the date inscribed on the concrete have been found.
Exploration Log 2
Date: 4/4 2017
Exploration Team: D-356
Subject: SCP-XXXX-1
Equipment: A shoulder-mounted video camera.
Aim: Gain a further understanding of SCP-XXXX-1, determine the significance of the 12/12/2016
[BEGIN LOG]
D-356 enters SCP-XXXX-1 without complications. The surrounding area remains unchanged, apart from a large floating life-form in the sky. The life-form partially resembles an ichthyoid but is otherwise unidentifiable. D-356 pays it no mind but points to the now uniform line of rooms. The room at the front of the line bears a sign reading, "this story is over. I have left you much more than a mere introduction." D-356 moves to the next room, opening the door and entering.
UN: "I visited mum today." A house typical of those seen in the suburbs of the 1940s materialises atop a grassy hill. UN taps D-356's shoulder, startling them. "She looked upset."
UN begins walking towards the house, a pathway forms in a trail behind him. D-356 follows suit
UN: "There she is." UN opens the door, revealing an infirmary with an elderly woman on life support. She opens her eyes and points at D-356.
Elderly Woman: "I'm sorry baby, I…" Her heart rate increases massively. "Please forgive me, tell her I'm sorry." Subject ceases movement, flatlining.
UN: "She wanted me to tell you that, but I wouldn't do her justice. She still loved us." UN stares down. "I've left you something, you're gonna have to prod your memory to find it though."
UN dissipates into a mist, forming a door with a keypad floating next to it.
[END LOG]
Exploration Log 2
Date: 4/4 2017
Exploration Team: D-356
Subject: SCP-XXXX-1
Equipment: A shoulder-mounted video camera.
Aim: Gain a further understanding of SCP-XXXX-1, determine the significance of the 12/12/2016
[BEGIN LOG]
D-356 enters SCP-XXXX-1 and enters the third room. The inside resembles a dilapidated studio apartment.
UN: "I've tried letting go."
UN is tied by the wrists on a lawn chair. They exhibit signs of malnutrition, bearing a skeletal appearance.
UN: "Seems I'll never forget."
[END LOG]
Addendum: [Optional additional paragraphs]
