The Mark XXXVII Armor (codenamed Hammerhead) was Tony Stark's thirty-seventh Iron Man suit and was designed to specialize in deep sea traversal. It was a part of the Iron Legion. It was destroyed during the Battle on the Norco.
The Hammerhead armor was created by Tony Stark sometime after the Battle of New York. As part of the Iron Legion, it took part in the Battle on the Norco, aiding Iron Man in his battle against Aldrich Killian and his Extremis-enhanced soldiers. During the course of the fight, a number of armors were destroyed, though they eventually managed to eliminate all of the Extremis Soldiers. At the end of the battle, the remaining suits that were not destroyed by Extremis Soldiers were destroyed when Stark activated the Clean Slate Protocol, including the Mark XXXVII.
The Hammerhead armor is designed for operation and travel in the deepest parts of the ocean and was built to withstand the extreme pressure experienced in deep sea environments. Similar to an Atmospheric diving suit, the Mark XXXVII is designed to withstand extreme outside pressure while maintaining a sealed, water-tight internal environment of standard atmospheric pressure. Following this design the armor possesses much thicker, re-enforced layers of armor, giving it a stout or bulky overall appearance in the torso and limbs. In order to maintain a sealed environment at extreme pressure, the suit reduces the space between sections by using large ball-joints at the knees, ankles, elbows, and shoulders, and by reducing or eliminating certain extraneous areas of the suit, like the neck.
Other traits that assist the suit in underwater conditions include mechanisms that allow the suit maintain buoyancy, allowing it to descend and remain submerged for an extended period of time before ascending back to the surface. The suit has its own internal oxygen supply that lasts for an unspecified amount of time. In order to accommodate operation at lower depths where light can no longer penetrate, the suit contains a series of high-power work lights to allow visibility.
Like other models of the Iron Man armor, the Mark XXXVII increases the physical abilities of the wearer, giving its user superhuman strength, durability, movement speed, and reflexes under normal conditions and retains some semblance of those abilities while under extreme pressure. The suit has the same repulsor based flight system as the other Iron Man armors; however, in order to move more efficiently underwater the suit possesses a pair of turbines located on its upper back. In addition, while the repulsors serve as its main weapon on land, the suit possesses torpedo based ordinance weapons suited for attacking enemies underwater. 
| Mark I • Mark II • Mark III • Mark IV • Mark V • Mark VI • Mark VII|
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Mark XVIII • Mark XIX • Mark XX • Mark XXI • Mark XXII • Mark XXIII • Mark XXIV • Mark XXV • Mark XXVI •
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|Mark I • Mark II|
|Spider-Man Suit • Iron Spider Armor|
|Iron Man Armor: Mark XLIX|