Optimus prime, a kind intelligent autobot leader you were great friends with and worked together constantly. until one day something changed in him every time you passed him he’d ignore you or say something negative,

he then changed completely his color scheme darker and his teeth sharper with sharper claws as well, he ended up starting a hunger for other cybertronians, you were walking through the base one day to see a trail of blood filling the floors and you decided to follow it, until you peeked in a dark room to see Optimus eating and gnawing on another cybertronian?!?!