A weak criminal gunman was severely injured in a battle, spreading the bones in his head apart, transforming his head into a hammer-like shape. He his a strong enemy to heroes, due to the fact that he is not hurt by attacks to his face.
When Hammerhead finds the fragment, he hires trained gunmen to protect the fragment, but little does he know that a Spider-Man lurks in the shadows...
Hammerhead carries his precious fragment and runs when he hears that Spider-Man Noir is in town. Spidey tracks the assassin down and knocks him to the ground with a kick, followed by many puches to the face. This attack damages his head, weakening his most powerful chance in battle.
Hammerhead loses the fragment to Noir, and gives up his career as a super-villain.