The man called Hammerhead was a criminal named Juan Tiburon. He had wide-set eyes, dark hair, prominent cheekbones, and wore a short moustache and beard.
Hammerhead planned and executed the theft of an American nuclear submarine (also called the Hammerhead). He abducted Dick Tracy and FBI Agent Jim Trailer when they discovered the submarine hidden inside a wrecked sailing ship in the Caribbean.
Hammerhead claimed that he was not motivated by money, but by ideology. He told Tracy that he had stolen the submarine on behalf of an organization seeking to establish a one-world government.
Hammerhead planned to launch a nuclear missile from the submarine to the destroy the island of San Luca, where an international anti-terrorism summit was taking place. Hammerhead's associate Roger Rotiart was the only member of the crew that was trained in how to properly launch the missile. Tracy and Trailer managed to free themselves from where they were being held on the submarine and acquired weapons. Tracy shot Rotiart before he could launch the missile and Hammerhead fled in SCUBA gear.
Tracy pursued Hammerhead and the two men grappled underwater. Hammerhead cut the air hose on Tracy's SCUBA gear, but Hammerhead was also cut in the struggle. Hammerhead's blood attracted nearby sharks, who attacked and killed him. Tracy was rescued by the Navy and the ship was recovered.
- "Hammerhead" is a type of shark with a T-shaped head. The character's features resemble this shark.
- "Tiburón" is Spanish for "shark".
- While it is possible that Hammerhead may have been one of the masked divers shown capturing the submarine, the uncommon shape of his head makes this unlikely.