Thunderbolts* Forgot to Explain A Wild MCU Mystery From 3 Years Ago

Marvel Studios had the perfect opportunity to address a three-year-old mystery in Thunderbolts*, the most recent movie in the Marvel Cinematic Universe, but the chance was missed. Released in May 2025, Thunderbolts* brought together Yelena Belova, Ava Starr, Alexei Shostakov, John Walker, and Bucky Barnes as a brand-new superhero team, later confirmed to be the New Avengers. Bringing back these classic MCU characters tied up many loose ends, but there was one huge mystery that Marvel failed to address in the Phase 5 crossover movie.

Back in 2022, The Guardians of the Galaxy Holiday Special caught up with the titular cosmic team in the gap between 2019’s Avengers: Endgame and 2023’s Guardians of the Galaxy Vol. 3. While Drax and Mantis tried to get Kevin Bacon as a Christmas present for Peter Quill’s Star-Lord, Nebula gifted Rocket Raccoon something far more intriguing: Bucky Barnes’ vibranium arm. Director James Gunn confirmed this was canon to the MCU, meaning Nebula actually stole Bucky’s arm, which had last been seen in 2021’s The Falcon and the Winter Soldier. However, Thunderbolts* completely ignored this MCU plot development.

Rocket’s obsession with Bucky Barnes’ arm began during Avengers: Infinity War, where the pair first met on the battlefield in Wakanda. Bucky and Rocket then fought together during the Battle of Earth in Endgame, but it was still surprising to see Rocket actually get the vibranium limb as a Christmas gift in The Guardians of the Galaxy Holiday Special. Nebula, with an “overabundance of Christmas spirit,” as James Gunn put it, removed the arm by force and took it back to Knowhere. An act this aggressive and transformative for Bucky would have surely left its mark, but he hasn’t mentioned it at all.

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Bucky Barnes’ evolution into a Congressman is somewhat unbelievable enough, but side-stepping his arm being stolen and him somehow acquiring another one makes this storyline rather confusing. Bucky should have addressed the fact that his arm was stolen in Thunderbolts*, especially since some focus was put on his arm, such as it being in the dishwasher or being forcibly removed by Lewis Pullman’s remarkably strong character, The Sentry. Bucky’s arm has been taken off his body several times, besides by Sentry, including by Aya in The Falcon and the Winter Soldier, and by Nebula (off-screen).

Sebastian Stan is set to return as Bucky Barnes’ Winter Soldier, now a member of the New Avengers, in 2026’s Avengers: Doomsday. While the Guardians of the Galaxy haven’t yet been revealed to be coming back, it’s possible Bucky could come face-to-face with Nebula (Karen Gillan) and Rocket (Bradley Cooper) in the MCU’s Phase 6 event films. This could provide the perfect opportunity for Marvel Studios to finally address this plot hole, three years after it was first created in The Guardians of the Galaxy Holiday Special.

What do you think really happened to Bucky Barnes’ arm? Let us know in the comments!