Spark

Spark is a ball of powerful concentrated energy that resides inside the living body. In most civilizations, they're heavily associated with "souls" as they appear at birth and depart at the death of a living being. Forced extraction of spark will also lead to death. Sparks play important role in the life of living organisms: from making sure that the body follows its genetic code to serve as an additional brain, cable of processing emotions, and storing memory.
Spark is the source of ESPER, and randomized settings determine if bearers will have this ability, which ability, and how strong the ability from the start. For Cybertronians sparks determine also their CNA.
Upon the death of a living body, a spark departs to the dimension known as "The Well".

Physical Appearance

Spark looks like a ball of white light, floating in the air and invisible to the naked eye, with the expectation of cybertronians spark chamber, which due to specific structure renders them visible. It consists of two parts: the core, which varies depending on size class, and the spithasphere, the pulsing outer layer.

The core

There are 7 general size spark classes, which determine which living bodies they can occupy.

1. Microscopic: microorganisms, including viruses.
2. Tiny: from moss and tiny insects to flowers to animals the size of the mouse.
3. Small: from bushes to medium-sized animals like dogs.
4. Medium: from trees and big animals and humans and small- and medium-sized cybertronians.
5. Big: from large trees and animals to big cybertronians.
6. Large: this class for especially large beings like cityformers.
7. Planet: those sparks exclusively occupy beings known as Planet Titans.

When spark departs from the Well, it seeks a body that can house it. There are different rules for each species, depending on the type of lifeform.
For organic lifeforms, sparks stars segmentation: a process of dividing itself into microscopic segments that will occupy cells. Those parts are still functioning are one spark as they occupy one body. They concentrate around the brain. If the brain is absent, then spark concentrates around other important organs.
For biometallic lifeforms and energoids in most cases sparks stay in one piece, but sometimes segmentation can happen here: if a spark is too big for the nearby body, but there are multiple of them, it will divide itself into fitting sizes, creating split-sparks. Those sparks function separately as they occupy different bodies, but they still retain connection.

The spithasphere

This is the outer layer of the spark, that pulsates, similar to an organic heart. Pulses are what keeps the spark functioning and in some cases - the entire body. In organic bodies, those pulses are synched with the heart. If the heart is absent, the spark assumes this role automatically.

The cycle of life and death

The cycle consists of three main stages: birth, death, and the Well. It was created as soon as the first living being formed in the Universe and will continue until the ultimate death of the universe.

Birth

When a spark leaves the Well, it begins looking for a fitting body - not every matter is counted as a vessel. The body must be formed the base for its species, meaning they will not pick an incubating body that yet to be formed. For example, a fetus that is being carried by a pregnant being is not a formed body yet, so spark will not choose it. Sparks will only appear nearby a few days before birth, usually swarming around and waiting for this moment. Same deal with eggs and even seeds. If someone has an ESPER ability to sense sparks, like Bumblebee, they easily tell who is about to give birth or which seeds are about to sprout.
In the case of biometallic life, like cybertronians, the process is different. Because they cannot reproduce, in order for a spark to occupy the protoform, it must be activated. This is only possible with the AllSpark.

Death

If the body is destroyed or heavily damaged, a spark will leave it as it cannot sustain it anymore. If a body ages over time, a spark will slowly lose its grip on the body and will leave it behind, causing a natural death. If a spark is forcefully pulled from the body, it will die within minutes. When people describe their near-death experiences, the light they see at "the end to a tunnel" is in fact is their glimpse into a dimension known as the Well - a place where spark departs after leaving a body behind.

The Well

This is a subdimension of the known Universe, a place where sparks come from. It looks like a large pool of swirling light, containing countless sparks that arrive and depart non-stop. When spark arrives here after the demise of their body, they undergo the process of cleaning - every information that was stored on it will be deleted. After this, a spark can depart to seek a new body. Because time flows differently here, the same departed spark will appear in the main dimension only after 10 years after the death of the previous vessel. For split-spark even longer, because it cannot starts cleansing until it becomes whole.
Sometimes, at a very rare occasion, if fading consciousness of the dead individual holds onto some memories too hard, those memories can withstand cleaning and pass into different life as echoes.

Type

Metaphysical, Astral