Sebastian Stan Reveals What He Did When He First Put the Winter Soldier Arm On

Bucky Barnes' prosthetic arm might be representative of a serious transformation for the character in the Marvel Cinematic Universe, but it seems like Sebastian Stan had a little bit of fun the first time he slipped it on.

Stan said during an appearance on Earth's Mightiest Show that while he didn't indulge in doing "the robot", he did have a lot of fun just grabbing things and making sound effects.

"I did not do the robot," Stan said. "I was just more like going around like grabbing things left and right, making sound effects and I think they were always like telling me 'you know you don't have to do those sound effects when you do the punches' but [I] couldn't help it."

As fans of the Marvel Cinematic Universe know, that prosthetic arm has undergone a lot of changes since it first debuted in Captain America: The Winter Soldier with the first one definitely more robot-like and that would be conducive to interesting sound effects. It's that changing nature of the prosthetic arm that Stan reflected on, noting that the arm has become something of a metaphor for Bucky's progression.

"The first arm that was in the Winter Soldier movie, the material was really hard, and it was very hard to actually move in it... but it actually informed the way I was moving at the time because it was just like carrying this thing, so it totally affected me in a great way," Stan said. "It made me discover the character in a way. And so, I guess to some extent, so does he. He's just becoming more comfortable in his own shoes and arm as he's progressively getting older."

Bucky's latest version of the arm made its debut in Avengers: Infinity War, but the arm -- and Bucky's journey -- may have come to an end. Bucky was sadly one of the casualties of Thanos' snap in the film and Stan explained that his character's fate is one that he wasn't told about until right when it was happening. Stan revealed that the moment was his favorite Infinity War outtake, a story that matches what he told fans during his appearance at Wizard World Philadelphia earlier this year.

"I remember the day on set and James Young, who is one of my talented, glorious stuntmen ... on this film, came up to me and told me what was happening," Stan explained, noting that Young told him they were filming a scene in which Bucky disappears.

"And I was like, 'maybe this is it.' And I remember Anthony [Russo] was talking to everybody, and I was like, 'Anthony, do- OK, I'll wait. Uh, do- am I- uh, is this it?' And he was like 'No, well, you know, maybe. But not really. Well, I don't know.' So, that's the way that day went."

Avengers: Infinity War is now available is now available as a digital download and on Blu-ray and DVD on August 14th. Ant-Man and the Wasp is now playing in theaters. Other upcoming Marvel Cinematic Universe movies include Captain Marvel on March 8, 2019, the fourth Avengers movie on May 3, 2019, the sequel to Spider-Man: Far From Home on July 5th, 2019, and Guardians of the Galaxy Vol. 3 in 2020.