Avengers: Endgame - 13 Best Callbacks To The MCU

In The Avengers, the entire reason that S.H.I.E.L.D. even considers including the monstrous and dangerous dual personalities of Bruce Banner and the Hulk on their super team is thanks to Banner's first-hand knowledge of gamma radiation, the substance that led to the birth of the Hulk.

It was established that the Tesseract gave off gamma radiation as well, meaning that Bruce would have a better chance of helping them track it and understand it than anyone else. At the time, this was little more than a serviceable plot point to give S.H.I.E.L.D. believable motivation to even have Bruce on the team. But Endgame turns this seven-year-old plot point into a setup for one of the film's biggest payoffs.

Once the Avengers have assembled all of the Infinity Stones, it is Hulk who steps dons the gauntlet and snaps his fingers because it turns out that all of the stones emit gamma radiation and he is the only one capable of surviving such an event. As he himself says, "It's like I was made for this". It's a tremendously gratifying payoff that feels hard-earned.