Joseph Martello (Earth-21399)

Early Life
As a child, Joseph Martello was shot in the forehead by gang members. His life was saved by surgeon Jonas Harrow, who repaired the damage to Martello's skull by grafting a steel plate over it.

However, Martello suffered from brain damage as a result of his injuries, and he grew up to be a sociopathic criminal. He earned the nickname "Hammerhead" for his practice of headbutting rival gangsters to death, and eventually became one of the favored enforcers for Italian mob boss Silvio Manfredi.