Giant-Man (Ultimate Avengers)

Henry Pym was the former head of the Super Soldier Program before being fired for irresponsibility and being replaced by Bruce Banner. He once took the identity of Ant-Man with a helmet which controls his ant-farm, and abilities to alter his size developed from studying his wife, Janet's mutant powers. Becoming Giant-Man, he joined the Avengers but was unhappy working under the leadership of Captain America, thinking him too old-fashioned. His irresponsible actions led to the temporary disbanding of the team before returning to help with the fight against the Chitauri. Despite his size, Pym was easily defeated by the Hulk.[1]