This is one the Chaos Terminators that I started converting before I quit playing a few years ago. I used a Tyranid Frag Spore Mine for his head. I also hollowed out a spot in his gut and put a zombie head in the gap.
I have not decided how I am going to arm these guys and it would also be hard to paint with arms on so they do not have any arms yet.
Next time I hope to have this guy primed and a few layers of paint on him.