Dimensional Filaments

Dimensional Filaments are a 7D particle that exists in the boundaries between dimensions and universes, so pretty much anywhere and everywhere. This particle's job is to isolate the universes and dimensions so nothing leaks between them, potentially causing a lot of havoc.

Mechanics
The particle exists as a 7D sheet, more commonly known as Spacetime Fabric, covering every corner of the multiverse and outside of it. Trying to pass through the fabric that it creates, it effectively loops in on itself. Trying to go into dimensions leaves you in the current one, reaching the edge of a universe just sends you to the other side with no transition.

While Spacetime Fabric is very hard to break apart, its not impossible. Causing various effects, many of which are unpleasant, as different universes and dimensions start leaking to that spot. However, without high amounts of damage or energy keeping it broken, it will very quickly stitch itself back together within fractions of a second as the particles can multiply very quickly.

The strength of the fabric is different in every part of the multiverse, this can be felt by how strong gravity in the universe is. The stronger the fabric, the less gravity is, this is due to the fabric bending less when exposed to any kind of matter. There have been no universes found without some give in the fabric. This particle in an area where gravity is weaker has a strange effect of constantly multiplying, causing universes to expand. Even accelerating expansion when certain conditions are met. This caused by the universe almost pulling itself apart and the particle having to adjust the amount it has to stop it from happening.

Study of Dimensional Filaments
Dimensional Filaments are an unknown particle that not much is known about. Only those who are very sound with the multiverse itself really know what they are. Even then, there are very few ways to study them due to their fabric creating nature. So far the study of this particle is very slow, and very little is actually understood about them.

Other Effects
This particle can turn itself into 7D polymers in rare situations, these are known as Cosmic Strings. These strings act in very strange ways, where they can act as different fundamental particles, and even make holes in the spacetime fabric, making wormholes. These Cosmic Strings are only really found in a few areas where the fabric is particularly flexible, and even more rarely there are naturally made wormholes from multiple lightyear long strings.

This particle has incredibly chaotic behavior when exposed to other reality substances. One known effect is when Aether, isolated Dimensional Filaments, and large amounts of H2O come together. It creates a dangerous liquid known as Cosmic Aether, commonly known as Spaether or Spacether. This purple liquid is nebulaic and starry in nature, it looks like staring into a portal to the depths of space. This corrupted form of Aether can create very strange lifeforms on the environment it is in thanks to the effects of the Dimensional Filaments. This liquid can potentially even create a pocket universe within the size of a lake, and perhaps create some lifeforms that may not be a good idea to let out.