The Avengers win in Wakanda by a hair. In the last desperate attempt to slay the titan, Thor had thrown Stormbreaker, just as the fiend made his snap to wish. Right then the ax had hit the alien's arm, chopping it clean off and sending it flying with the gauntlet. In the ensuing chaos and confusion, as multiple fighters tried to catch and carry the weapon, just to fade into dust in the process, the God of Thunder was able to hold Thanos down, while the gauntlet landed in front of Bruce. Scared and unsure, but also desperate to help, the scientist picked up the glove, removing the arm inside, and then, risking it all, put it on, hoping to right the wrong. And he did.

He was able to undo the damage done by the aliens, not just the snap, but so much more that had occurred, where he had not been able to help. It drained him, and when it was over, he needed to be rushed into treatment by Shuri, Strange and Tony, whom he had teleported to the battlefield, along with the other stranded fighters. They were able to save him, although it was mostly his own body who did the repairing. That's when the scientists discovered, that due to the supersoldier serum, which the Hulk had adapted, he was able to regrow body parts.

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After experimenting a little, they found out that Steve and Bucky were also able to do so, even if they would need medical help for it to work out, and speed up the process. After some thought, Bucky decided he wants to regrow his arm, and Stark and Shuri come up with a contraption to help him. He has to go into a tank, where his vitals will be in check, the flesh can remain open and grow on it's own, but with some help to get the muscles up to speed soon.

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