(Marvel's Iron Man & Hulk: Heroes United/2013) When Zzzax, a seemingly invincible, energy devouring monster threatens to destroy the planet, Marvel?s unlikeliest pairing of Avengers is mankind?s only hope. Alone, neither can defeat the awesome power of Zzzax. As a duo, they just might have a chance ? if they can find a way to work together without smashing heads before time runs out.