Yellow Sparkeaters + some who are Sparkeaters
Sparkeaters happen when a mech eats the spark, of another mech, in which they form into one of several different types. Only the spark is needed to become a sparkeater and eating other parts of a Cybertronian will not turn someone into one.
‘Normal’ sparkeaters are the most well-known in myths and are the most common type one can turn into, but in the wild it is rare to see one as their exposed sparks are vulnerable weakspots. These are the most monstrous and least conscious.
Sirens, which are called that for their songs that sound like emergency sirens to anyone not afflicted by their curse, lure their prey using their voices. For some reason, only flier or aquatic alt modes can be sirens.
Headmasters consume their prey by decapitating a mech and using their body as a food source and vessal for other activities. Typically they need to move on to new bodies after a couple of vorns. You can tell one is a Headmaster if they survive decapitation. Do not use this method casually. People who turn into Headmasters are not brutes or fighters, typically avoiding them if needed.
Energon Eaters do not need to consume entire sparks to sustain themselves, instead only needing innermost energon and can typically leave their victims alive. Only beast modes can be this type, and typically the more charismatic turn. You might be able to tell one is an Energon Eater by their fangs and slited optics but like. Those are also just common traits a rando can have.
The Faceless. The Faceless’ face melts into one solid block, losing their sight and their own voice, but they can perfectly mimic the voices of anyone around them. Like ‘normal’ sparkeaters, their bodies morph and change into a new form, being lankier and taller, an average mech growing to be equivalent to shuttles in height. They have four tentacles from their backs that are jammed into sparks to scifon energy directly. No one knows what qualities make a Faceless, some theorizing it might be intelligence as these are some of the smartest types of Sparkeater. It is very obvious to tell who’s a Faceless. They typically live alone.
Amalgamates are the rarest Sparkeaters. It is said they are related to Amalgamous Prime, mechs that when they eat a spark, mutate into gaining their mods and kibble. The key factor is that they do not gain any outliers or knowledge, only physical traits. These mechs do not look like normal mechs, instead being a mish-mash of limbs, mods, and kibble. They can sustain a normal-looking form but this requires a lot of energy, and so typically only happens after a meal. It is theorized that triple or more changers are the ones most likely to become one, but because of the usefulness of multiple alt-modes, experimentation is limited.
Mechs who are Sparkeaters:
Chromedome, Brainstorm, and Skullcruncher are Headmasters.
Brainstorm was fascinated by Sparkeaters and wanted to find a way to circumvent the whole ‘eating people’ part of it, but unfortunately, no one cared enough to help him. So he tries to find a way to become a Sparkeater without eating a spark, failing over and over again, until one day he decided to bite the spark bullet and try to find a spark to eat without killing someone. Someone suicidal, perhaps? He gets a spark from... Someone giving it to him, and he eats it, becoming a Sparkeater. Four vorns later he meets Chromedome
Still thinking of how exactly Chromedome came to eat a spark, but it was during his police duties and Prowl saw it. Chromedome was actually able to find a way to avoid eating sparks, and that’s by eating emotions. When he does mnemosurgery, he removes the emotions of mainly unpleasant (but sometimes pleasent if he needs more) memories. The memory will be there, just without any associated memories to it. Later on Brainstorm meets Chromedome and Chromedome helps share his secret to not eating people with Brainstorm, teaching Brainstorm some mnemosurgery. Using this process, they do not need to lose their bodies. They can still survive decapitation.
Skullcruncher wasn’t always his name and only became his name after he became a Headmaster and he well... Crushed skulls to get new bodies. He became a Sparkeater by being forced to eat the spark of a fallen ally by an Autobot. Nowadays he typically gets bodies from his friend, Krok.
Thunderblast and Siren are sirens, having only sparks left to consume in a survival situation.
The accused:
One can tell someone is a siren by their beautiful voice and/or voice-based ‘outliers’. Tarn gets accused of being a siren. A lot. When he shares that he had a frame change, the accusations only grow.
Soundwave gets accused of being a faceless and/or siren as well because of his outlier that can mimic voices, but one conversation with him normally dispels these theories.
