This dimension is superficially based on the real world. There are cities, buildings, landforms, etc. parallel what we know as the modern, physical world, and time passes in generally the same way. If one were to drive on a highway or walk down a street, there would be people, cars, etc. moving about and activities taking place, so at first glance it is imperceptible from the real world. Physics and biology are as they are in the real world, except when they are not.
General, the dimension is vaguely Lovecraftian, and contains impossible architecture, abominations, apparitions, etc. though it might take the visitor some exposure before they interact with these unique features. Being that it is a dimension parallel to the one we inhabit, the people there are generally autonomous. When they encounter an anomaly, depending on the circumstances, they may react as though it were familiar and normal, or unfamiliar and interesting or frightening. Neutral anomalies such as subtle geographic distortions, duplicate items, etc. go unnoticed, but overtly strange or threatening ones will conjure a fairly predictable reaction.
The dimension appears to choose targets and manipulate their stimulus to guide them to areas, or to influence them to perform certain behaviors. Another phenomenon is the use of negative stimulus, such as a sudden illness, hallucinations, or visual distortions to push the target along their path. It is not known what is the ultimate consequence of failing to heed the stimulus are, but it's theorized that the dimension maintains a certain "draw distance" for the targets (or, possibly, all individuals) and it may force the given drawn environment for the individual/target to occupy different space. It is not known what ultimately happens to the targets/individuals -- whether they die, or reappear in a different location or dimension (such as with a wormhole).
Abominations, anomalies, and apparitions are the three basic classifications for distinct dimensional behavior, or deviations from the expected physical reality.
Abominations fall into two categories:
1 - Malevolent - threatening entity that has a reasonably perceptible motivation to destroy objects or people. It doesn't matter whether the malevolent abomination leaves the waste or somehow consumes it. Malevolent entities tend to lock onto a target and chase it until, either, they find the original target or locate a new one. Because they rarely show fear, or retreat, it is difficult to dispatch with a malevolent entity without outright destroying it
2 - Animalistic - this entity can be thought of as "neutral". While they can have a threatening appearance, they avoid confrontation unless, like a familiar animal, for the purpose of obtaining food (if the entity is "carnivorous") or defending itself. While animalistic abominations aren't outright hostile, they can be fearsome once provoked and will need to be handled in a similar manner to a malevolent entity unless it is one that can be scared away. The best practice is to avoid provoking one unless certain of either its behavior or one's means to destroy it
Anomalies are, in generic terms, instances where the Discontiguous Dimension physically deviates from the real world. It is impossible to describe every possible anomaly, though some examples include things like:
1 - Changes in physical architecture
2 - Instances of reference*
3 - Teleportation
4 - Subordinate dimensions**
5 - Deviations from known physical/biological laws
* "Instances of reference" describes a stimulus only meaningful to the target, placed with the possible, apparent goal of influencing behavior
** A "subordinate dimension" describes an area within the dimension which appears, to the observer, to be a separate dimension due to the concentration and/or intensity of the anomalies there. However, it is always tied, in one way or another, to the Discontiguous Dimension.
Apparitions are beings within the dimension which interact specifically with the target and may or may not be perceptible to other non-apparition individuals. Typically, the target will notice the apparition due to its familiarity. When it comes to apparitions and instances of reference, it's been observed that these two instances which draw on the target's subconscious. They may take the form of old items, expected items or information, or persons known to the target. This phenomenon suggests a conscious force with psychic abilities and sufficient awareness to plan and react to the target's own actions.
This dimension takes the form of a subway station. It can be discerned from a normal train station because the entrance will appear in a place where the observer, if acquainted with their locale's geography, will know there to be no entrance to any station. The appearance will be congruent to the locale's architectural style, and there will be people inside the station, but they are anomalies (animalistic), rather than extant individuals. Electronic signs, especially showing destinations, may be garbled or static, and maps and signs may contain errors only on close examination.
Individuals may pass in and out of this dimension at will, though the destination of the train is commonly dictated through instances of references. E.g. it will take you where dimension wishes to take you.
The main danger of Transit is present in the anomalies that inhabit it. If the individual causes certain types of disruptions - ex. attacks an anomaly - every anomaly in the station will mob the person until they are dead, even to the detriment of their own personal "safety". For one extreme example, a group of observers entered Transit. One of the observers ahead of them pushed an anomaly and caused it to fall on the ground. The rest of the observers watched in horror as the anomalies chased the offending observer until they caught him as a mass upon the tracks. The train arrived and plowed through the anomalies, creating a level of gore only seen in certain war scenarios or massive industrial accidents.
This dimension takes the form of a nonsensical arrangement of hallways and rooms. It is easy for an observer to recognize this dimension as an anomaly due to the illogical and non-functional architecture -- hallways winding purposelessly, corridors that turn back on themselves, dead ends, etc. The appearance may or may not, to some degree, be congruent with the locale's architectural style.
The Backrooms have been reported in known extra-dimensional experiences, and commonly occurs as a labyrinth of humming florescent lights, and floors and walls of yellowed cream/beige carpet and wallpaper. Few other reports have described the backrooms as dimly-lit cinderblock corridors or as office hallways. Other descriptions have been scarce and not detailed enough to be conclusive.
This dimension presents as a massive storage yard for a variety of cement structures ranging from large blocks, Jersey barriers, or cube- or jack-shaped elements such as those used for breakwaters. Arrangement of the objects commonly necessitates finding a path over or through. Some observers have reported the possibility of descending below surface level, but have stayed on the surface in order to avoid any unfortunate accidents. It is possible those have have descended haven't survived the experience. It's safest to avoid a descent into the blockades
Most reports of the dimension have described the weather as clear and sunny, ranging in temperature from 70-85F. Rare others have described their frustration at trying to navigate the Blockades in a blizzard or constant, driving rain. Apart from the sound of rain, when reported, all observers have described an eerie and absolutely silence in this dimension. No observer has reported the ability to see the horizon, due to the height of the structures being stacked. The furthest visible distance reported has been approximately one linear mile. Whenever an observer climbs to the top of a pile of barriers, there always seems to be a stack just high enough to block them from seeing the horizon, even if they go to the offending stack and climb it.