Iron Man & Hulk: Heroes United (2013)

Plot

Iron Man and Hulk unite to confront a formidable new menace threatening Earth. When Hydra scientists attempt to amplify a Stark Arc Reactor using Hulk's Gamma Energy, they inadvertently create Zzzax, a destructive entity of pure electricity. With time running out, Iron Man and Hulk must navigate a gauntlet of fierce Wendigos, lethal robots, and the fearsome Abomination. Their greatest challenge, however, may be learning to collaborate effectively without letting their tempers flare. Can these iconic heroes set aside their differences to thwart Zzzax's plans for global chaos?