Apex

Bruce Banner, desperate to rid himself of the Hulk, bombarded himself with an enormous dose of gamma radiation. Instead of a cure, this tragic experiment spawned a colossal kaiju-like creature called the Apex. The Apex possessed the terrifying ability to create an army of Gamma Beasts, plunging the world into chaos. To combat the threat, the Avengers constructed massive mechas, but were overrun and defeated. Over the next decade, these surviving heroes valiantly repelled waves of gamma monsters, but when the Apex reemerged, the situation became dire. Initially, Banner refused to get involved, haunted by guilt over the destruction he caused. However, he provided Sam Wilson with the "Mighty Avenger Protocol," a contingency plan originally devised to neutralize the Hulk.