[@ZxyxZemon][@Sanity43217] I've had something similar in mind, gamma mutant OR someone who has a demon placed in their body. 

Gamma idea - So, basically - A person that tried to subject themselves to the same thing that Dr. Banner did but it didn't work out properly, at all. Said person grew in size and strength but their intelligence got lowered by a lot. Multiple mouths appeared on their body and a insatiable craving for [i] meat [/i] appeared. 

At first, in their origin, they were no smarter than a crazed animal. Hunt, kill, eat. As he devoured more and more humans and what not, their intelligence grew. Up to the point of an average human (from where we'll start the story) but still with the craving for flesh.

Just a rough idea I had atm.