insecuriosity

We all know empties. One of the most common of Cybertronian monsters, bar perhaps the Sparkeaters, Empties often serve as a reminder to stay together- Don’t venture out into the wilderness of Cybertron on your own, and don’t set a foot in the darker parts of the Dead End! 

And of course, don’t go hungry for too long, or you’ll BECOME one!!

…but that does not seem to hold up. Not every mech that dies is guaranteed to get up and become an empty. Mecha with slit lines who bleed their energon into the soil of Cybertron are not guaranteed become empties, and even a slow starvation doesn’t mean you will become an empty.
So what is it that transforms a normal mech into a mindless drone with a hunger for pre-digested mech-fuel?

The answer is not far fetched or surprising. Dark energon.

With all the myth and superstition surrounding this dark fuel, it is very doubtful any mech would voluntarily consume it. In small doses it is already enough to transform mecha into horrible monstrosities!
No, there is a reason that Empties only pop up where the situation is dire. When there’s not enough energon to go around, mecha get desperate. They take fuel from places they normally wouldn’t. They are too faded and listless to go through the filtering process, if they even have a filtering system at all.

As they drink from unfiltered and odd sources, small traces of dark energon come into their system. Nothing too dire, nothing transformative. The only way you can see that someone has been drinking dark-energon contaminated fuel is after they have died.
If their spark signature falls away and their frame grows cold and motionless, they managed to die as a creation of Primus. If they get back up, with a hungry look in their optics, it’s already too late.