Hammerhead is a member of the Triumvirate of Terror alongside Thunderboot, Pile-Driver and their leader, the Mad Thinker. Hawkeye was held prisoner after Hammerhead defeated him in battle. The Mad Thinker devised a scheme to destroy all the Avengers while their leader, Captain America was on another assignment. Goliath and the Wasp received an SOS signal and followed it to an excavation site where the two Avengers came into conflict with Pile-Driver. The steel gloves of Pile-Driver granted him enhanced strength and he was able to take down both Avengers when he struck them with a steel girder. Scarlet Witch and Quicksilver were defeated by Thunderboot and all five Avengers were strapped to a restraining shaft. Mad Thinker was off his calculations and did not anticipate Hercules to arrive at the mansion. Hercules engaged his enemies and managed to free his teammates when he smashed the restraining shaft. The Avengers made quick work of Hammerhead and the rest of the Triumvirate of Terror.   

Creation

Hammerhead was created by Roy Thomas and Don Heck in 1967 and first appeared in The Avengers # 39. 

Powers & Abilities

Hammerhead had an armored helmet that provided him enhanced durability, striking power and resistance to injury. Hammerhead's helmet was strong enough to withstand a blast from Hawkeye's explosi-shaft arrow.