Sunder was originally an Autobot psychologist who practiced a form of mind surgery called Mnemosurgery, allowing him to enter and manipulate the minds and memories of other Cybertronians. Over time, repeatedly exposing himself to the thoughts and traumas of others caused him to lose his sanity. Eventually he became a notorious serial killer known as the "Tetrahex Ripper." What makes Sunder especially frightening is that his powers evolved far beyond normal psychological treatment. He could alter memories, personality, and even a Transformer's perception of reality. At one point, his abilities became so dangerous that authorities removed his optics because merely looking at someone could allow him to affect their mind. Sunder is a tall, thin Cybertronian with a skeletal, almost corpse-like appearance. His armor is mostly gray with dark red accents, and his face is gaunt and unsettling. After his powers became too dangerous, his optics were removed, leaving him with dark, empty eye sockets that make him look even more disturbing.