Protoform X

Protoform X is an experimental Cybertronian.

Physiology
being the only one of his kind it safe to assume that Protoform X stands over 10 feet tall if not more.

Rampage as he is otherwise known as has an experimental spark that is almost indestructible and can only be damaged or destroyed be an Energon blade.

even if he is damaged to the point when he is in several pieces aslong as his spark is undamaged he will rebuild himself.

This invincebility is gifted to him at the cost of his sanity, as he is sycotic in every way. Unlike all other transformers he feeds on the emotions of others, especialy negative ones like pain (both emotional and physical) and fear.