Rocket Raccoon should have easily gotten Bucky's metal arm five years ago, and if one were to debate Avengers: Infinity War that moment played out differently.
Rocket Raccoon could have gotten Bucky's arm long before the Guardians of the Galaxy holiday special, since Avengers: Infinity War was supposed to give him an easy vibranium arm. One of Rocket's recurring jokes in the MCU is that he's interested in acquiring other people's body parts made of metal or technology. This led to a memorable exchange in Avengers: Infinity War when Rocket met Bucky Barnes and asked him how much it would cost him to buy his vibranium arm. Even though Bucky told him the arm wasn't for sale, Rocket still believed he'd get it eventually.
The Guardians of the Galaxy Holiday Special puts a surprising twist on the joke, as Nebula sends Bucky Rocket's arm for Christmas. This moment raises a lot of questions about how Nebula managed to steal Bucky's arm and what Rocket will do with it. While it took years for Marvel Studios to cash in on the tease that Rocket would get Bucky's arm, there's an easier path to the same result. In fact, Rocket should have gotten Bucky's arm in Avengers: Infinity War ending, if one controversial aspect of the Thanos snapshot was different.
Why Bucky's Arm Shouldn't Have Disappeared In Infinity War
Bucky's vibrating gold arm was the first thing viewers saw in Avengers: Infinity War that started to disappear after Thanos interrupted it, but the decision has been controversial. The confusing factor is that the gun that Bucky cared about hasn't gone away. While the film does suggest that superhero suits and clothing disappear with everyone photographed, Nick Fury dropping Captain Marvel's pager also suggests that some items may be forgotten. It could be argued that Bucky's arm disappeared because it was part of his body, but it's also important to remember that he only had it for a few hours.
The rules about what will and won't disappear when photographed by Thanos are not entirely clear, but Bucky's new arm is more like a borrowed weapon (like the gun he carries) rather than directly attached to him thing. According to the Russo brothers (via Comicbook), the fact that Bucky did wear the arm was the reason it disappeared, as they say that anything belonging to someone's identity disappears when snapped. While Bucky's metal arm is synonymous with his appearance, the one in Avengers: Infinity War is brand new Therefore, he does not have a deep history. It could have stayed back and let Rocket grab Bucky's arm.
How Nebula Got Bucky's Arm & Gave It To Rocket
Instead of Rocket being able to grab Bucky's arm in Avengers: Infinity War, the MCU now needs to explain how Nebula used it as a Christmas present in 2025. The answer may come from Guardians of the Galaxy Vol. 3 or Thunderbolts (which already confirms that Bucky has a new arm). Currently, the only explanation comes from James Gunn. He said on Twitter that Nebula came to Earth with a strong Christmas spirit and ripped off Bucky's arm as a Christmas present for the rocket. Whether this is Marvel Studios' MCU canon backstory or just Gunn's headshot remains to be seen.