Sergeant Mendoza, or "Dozer" as he's known to his friends, was considered a master in large weapons systems. He discovered several new ways to implement older firearms, forcing rewrites of every major weapons manual. Colonel Jackson Dane saw the need for a man of his abilities and procured him for the second generation of Team 7.
After receiving the Symbiotes at the Transylvanian vampire enclave, Dozer went AWOL with the rest of his team. But his symbiote made him so big and so heavy that he became unable to move by itself. So Wearing designed him a special suit for him to fit in, and to help him moving. The suit is so big that it contains a complete medical crew in one of its leg. The armor is also more armed and armored than a battle tank, which suits Dozer very fine as he loves big guns. To help him see his suroundings, Grail helped him by creating small flying orbs that Dozer can remotely control. The orbs then transmit him their 360 surroundings. It is not clear if they're parts of Grail's or Dozer's symbiote. As they're light blue, the former seems the more likely.
Due to the bulk and size of his armor, Dozer oftenly stays out from the action, as backup and fire support. Knowing that he can easily bring the house down to clear the way, his teammates can relief themselves of the question of the retreat. He's kept updated of the Sit Rep through the "eyes" of the orbs, and the telepathic links between the Symbiotes.
Grail taught Dozer how to control his size through oriental meditation techniques. However, when he experiences emotional stress (like when he saw Pilgrim come back), he loses his control and grows too big to stay up again. Throughout Wetworks' saga, Dozer has a secondary role, acting as the group's dummy brick and heavy firepower cleaner.
Until Drakken, the Vampire Nation's throne usurper, made his big gambit. He managed to capture the entire team and made Dozer grow like a 100 m tall pyramid. The pyramid was then an antennae that relayed the combined power of the captured members to ensure Drakken's power in an area 800 miles around Phoenix. In this area, nothing but what Drakken wanted could move. The day was saved by Pilgrim, as Drakken was oblivious of her werewolf heritage. Though freed, Claymore took upon himself to free Dozer of his tremendous pain and the zone of Drakken's influence. He killed Dozer and himself in the process.
With the changes in the nature of the universe from Captain Atoms visit, Dozer somehow came back to life and WetWorks.
The golden armor each member is joined with gives them increased strength, limited invulnerability and a mental link to one another as well as various individual powers. His symbiote caused him to grow to immense proportions, which he learned to control with mediation and the help of Grail.