Despite being a relatively new storyline introduced in Captain America #1 in 2005, Bucky Barnes’ transformation into the original Winter Soldier has captured the imagination of countless fans for over a decade.

The character’s boost in popularity is in part thanks to the Marvel Cinematic Universe. Sebastian Stan’s portrayal of Bucky is perhaps the most recognizable iteration of the character ever, since he first took on the character in Captain America: The First Avengers back in 2011 and his alter ego in Captain America: The Winter Soldier.

In particular, his bionic prosthesis has been the object of obsession and subject of discussion. Countless fans have found creative ways to replicate the limb for their cosplay endeavors, while others pore over the most minute of details to come up with theories. It’s also sparked a lot of talk about representations of disability in mainstream media, since the prosthesis is a replacement for the arm Bucky loses when he falls to his apparent demise in World War II.

However, Bucky Barnes' body is strange for reasons far beyond his prosthetic arm.

The facts herein have been gathered from the Marvel Cinematic Univeerse and various comic book multiverses. While there is the Winter Soldier program that produces other super soldiers, our list will focus on the original iteration, both in his identity Winter Soldier and as Bucky Barnes.

As usual, the list below contains spoilers for a lot of Marvel content, including Avengers: Infinity War.

Here are 20 Weird Facts About The Winter Soldier’s Body.

He's Fifteen

Bucky Barnes debut

Sebastian Stan’s portrayal of Bucky Barnes has become one of the most recognizable iterations of Captain America’s best bud. By the time principle photography began on Captain America: The First Avenger, Stan was already in his late twenties, thus solidifying the image of Bucky as a grown man.

However, in his very first appearance in the comics in 1941, Bucky is a plucky fifteen-year-old orphan who hangs around Camp Lehigh after his father es away in military training.

The MCU shows Bucky taking Steve under his wing, but the original teenaged Bucky idolized Captain America.

After undergoing extensive training to keep up with Cap’s superhuman body, Bucky successfully becomes his sidekick, becoming a symbol to unite the youth of America.

Cryogenic Statis

Bucky Barnes aka the Winter Soldier in Wakanda at the end of Captain America Civil War

When Steve Rogers gets revived decades after he gets trapped in ice, he looks the same age as when he is during World War II thanks to the cold keeping him in a state of suspended animation. Winter Soldier gets a similar treatment, albeit intentional on HYDRA’s part.

In order to help keep their super soldier in peak condition, HYDRA puts the Winter Soldier in a state of Cryogenic Stasis between missions.

As a result, he only ages during the brief periods when he’s actively working for HYDRA.

Another part of keeping him in maximum working condition is wiping his memory after every mission. Fortunately, Bucky is eventually able to start recovering his memories even though he can still be reverted into the Winter Soldier.

The real trigger word

Captain America Civil War Trailer Bucky Fight

Maintaining absolute control over the Winter Soldier is an integral part of HYDRA’s attempt to turn him into the ultimate human weapon. In addition to wiping out his memory every time he’s sent on a mission, HYDRA has also embedded some code words to activate the Winter Soldier program within Bucky and ensure complete compliance.

In the comics, just one word— “sputnik”—allows the speaker to trigger and control the Winter Soldier, but it’s been changed to several code words for the movies.

It may not seem like a significant change, but it does allow for one of the most chilling scenes of Capitan America: Civil War. Bucky desperately tries to escape before Zemo can finish reading the words, which hits home how traumatizing the experience is for Bucky.

His Arm Is Probably Titanium

Captain America The Winter Soldier Official Photo Bucky punching Shield

It’s rather well known that Bucky’s newest arm in Avengers: Infinity War is made of vibranium, courtesy of teen genius Shuri. However, there isn’t a solid canonical explanation for Bucky’s original arm.

That said, it’s most likely made of some sort of titanium alloy. Adamantium and carbonadium don’t seem to exist in the MCU, and since Cap’s shield— made of a vibranium alloy— can damage the prosthesis, it’s probably not made with vibranium either. After eliminating these metals, the most probable in-universe option is titanium alloy, which Tony Stark uses for his Iron-Man suits.

Sadly, Bucky’s brand-new vibranium arm disappears with him at the end of Infinity War when Thanos wipes out half the population of the universe.

The Bionic Arm Is insanely Heavy

Winter Soldier

Speaking of how heavy Winter Soldier’s metal arm is, the weight also affects the way he moves and holds himself. Stan’s portrayal in the MCU seems to take into the weight of the metal.

Upon close inspection, his posture is slightly off, suggesting that Bucky is compensating for the weight of the material with his stance.

While there don't seem to be confirmations of the bionic arm’s weight in the MCU, it’s safe to say it’s pretty damn heavy, considering it’s primarily made out of some sort of metal.

In addition, the Winter Soldier breaks the rear window of a car rather effortlessly when he flips onto it. This could hint that his body also weighs quite a bit, mostly likely due to his arm.

Extended Reach

Captain America: Civil War Trailer 2 - Bucky vs Stark

In Captain America Vol. 5, it’s revealed that his bionic arm can still function even when detached from his body. It’s not 100% confirmed how it’s done though.

It could be that Bucky maintains direct control of his arm thanks to some highly developed implants, or his arm can be programmed to work independently when it’s removed from him.

It’s not a feature that’s been used in the MCU yet. But perhaps it could be framed as a feature added by Shuri when she gave Bucky his new vibranium arm in Avengers: Infinity War, since not much is seen about the new prosthesis. Of course, Bucky would have to come back from his apparent ing first.

Palm Print Sensors

Black Panther Fighting Winter Soldier Bucky

Although Bucky has a high-tech bionic arm in addition to his skills, he still uses a lot of conventional weapons, including knives and firearms. In Winter Soldier #4, Bucky reveals that his arm isn’t the only gadget to receive upgrades throughout the years.

As the two near the end of their fight, Arkady of Project Zephyr attempts to attack Bucky with his own gun, but it explodes when he gets a hand on the firearm.

It turns out that the gun only works for Bucky because of its palm print sensors.

Of course, that brings into question how the palm sensors are able to recognize his left arm prosthesis, since he’s ambidextrous and is shown to use firearms with either hand. Then again, his prosthesis has muscle definition, so what’s to say his finger prints aren’t also on there?

Automatic Reload

Bucky ing the fight in Avengers: Infinity War

At one point in the comics, the Winter Soldier becomes the leader of the Thunderbolts when he helps some criminals escape. They initially work together just to attach a S.H.I.E.L.D. base to ensure the discontinuation of the Kobik Program, but the Winter Soldier ends up keeping the team together to help him protect the earth as the Man on the Wall.

During these events, Fixer gives the bionic arm several upgrades.

One of these upgrades is the ability to reload his weapons automatically. It’s not a feature in the MCU, but it would be pretty amazing to see the upgrade in action in real time.

And yes, the bionic arm still has muscle definition after the upgrade, of course.

Flame Thrower Arm

Bucky Barnes

Another major upgrade courtesy of Fixer in the Thunderbolts comics? Flame thrower arm!

Not only can Bucky emit bolts of electricity from the palms of his cybernetic arm - he can generate a literal stream of fire from it.

Sadly, this upgrade isn’t featured in the MCU either. We’ve seen Bucky block bullets with his arm, as well as the immense strength and incredible reaction time it gives him. It would’ve been an epic sight for him to shoot fire out of his arm as well, and it would’ve given him a leg up during his fight against Spider-Man in Captain America: Civil War.

In any case, Shuri’s a smart girl, so you never know what she’s hidden up Bucky’s vibranium sleeve.

He Gets The Infinity Formula

Bucky Barnes the Winter Soldier in Wakanda at the End of Captain America Civil War

In Fear Itself, the Marvel superheroes take on the Serpent - the Asgardian God of Fear who is set free by Sin, the daughter of the Red Skull. Bucky also assumes the identity of Captain America in this storyline. Sin is in possession of the Hammer of Skadi, and seems to end Bucky’s life in Washington, D.C. during her attempt to conquer the world.

However, Nick Fury gives him a dose of the Infinity Formula, thus reviving Bucky. He doesn’t continue being Captain America though,— he goes back to being the Winter Soldier because everyone believes he’s ed away. Thanks to the injection, Bucky gets to enjoy the life-prolonging benefits of the formula in addition to staying alive.