There is some serious stuff happening in the D&D game I'm running right now. I threw the players up against an old friend who had transformed into a monster (pictured). They killed him, like he asked.
Half robot (or warforged, in D&D), half troll. Once they killed and decapitated him, the warforged paladin burned away the troll bits, leaving what you see at the left. Not sure what a magical robot's brain looks like, but I think they would have one, and fancy wood seems a good material for such a thing.