I wanted a partner for Mr Knife and then while playing Arkham City I ran into Mr Hammer, stole the name and got an idea. I had the Baron Zemo head left over from Red Ghost and the headless Humungus body left over from my Scourge custom... sculpted the neck to match the scarred head sculpted some pant cuffs and sanded the veins and some of the musculature from the legs, modified a Thor hammer, and painted.