WARNING: The following contains spoilers for Black Widow, now playing in theatres and available for streaming through Disney+ Premiere Access.
Each entry in the Marvel Cinematic Universe is constructed with deep-cut references to various figures from Marvel Comics. That also extends to Black Widow, which expands the Russian corner of the MCU by expanding on the Black Widow program, the Red Room and the people connected to Natasha Romanov. Along the way, Black Widow features two pretty sly references to major Russian Marvel characters -- both through Alexei, aka the Red Guardian.
Red Guardian was meant to be an in-universe Russian answer to Captain America, even given his own variant of the Super-Soldier Serum that enhanced his strength, endurance and abilities immensely. However, it appears that his image was short-lived, with his bravado and pride earning some notoriety in Russia but seemingly nowhere else in the world.
His over-the-top love of Russia and his bombastic attitude even prompts Yelena to at one point to refer to him as the "Crimson Dynamo." In the original comics, Crimson Dynamo is an entirely different character than the Red Guardian. The original Crimson Dynamo -- created by Stan Lee, Robert Bernstein and Don Heck in Tales of Suspense #46 -- is historically a Russian equivalent of Iron Man.
There have been multiple people who've worn variants of the Crimson Dynamo suit over the years, with perhaps the most iconic being Anton Vanko -- the first person behind the armor. Vanko already appeared in the MCU, played by Mickey Rourke in Iron Man 2. Notably, Vanko was reimagined as a more direct parallel to Tony Stark and was restructured as a different villain, Whiplash. That version of Vanko even gained his own Iron Man-esque armor, but it lacked the distinct color scheme and design of the Crimson Dynamo. Still, the shout-out in Black Widow is a sweet-natured reference to the history of Marvel Comics; although, there are other hints of Crimson Dynamo potentially existing in the MCU.
Another classic Russian Marvel character makes an appearance in Black Widow -- or at least inspired a character who briefly appears. One of the other inmates alongside Alexei appears to be inspired by Mikhail Ursus, aka Ursa Major. Alexei is introduced in the present-day competing in arm-wrestling contests with the other prisoners. He mockingly refers to one of them as a strong "bear" and challenges him to a match. At first, it appears Ursus will present at least some form of challenge, but once Alexei utilizes his enhanced strength, he's able to easily break the man's arm. While different from his comic counterpart, these bear references make it clear who the film is alluding to.
Debuting in Incredible Hulk #258 by Bill Mantlo, Steven Grant and Sal Buscema, Ursa Major is a mutant who has the ability to take on a massive bear form -- giving him the strength and combat ability to hold his own against the likes of the Hulk. He's recently appeared as a member of the new Winter Guard who've come up against the Avengers. Typically a Russian powerhouse in the original comics, the reference to Ursa Major is instead used as a brief gag, reintroducing Alexei and showcasing how the dedicated soldier has changed over the years. However, like Crimson Dynamo's shout-out, it's a clever way for Black Widow to reference the comics that served as its inspiration.
Directed by Cate Shortland, Black Widow stars Scarlett Johansson as Natasha Romanoff/Black Widow, Florence Pugh as Yelena Belova, David Harbour as Alexei Shostakov/Red Guardian, O-T Fagbenle as Mason and Rachel Weisz as Melina Vostokoff. The film is now in theaters and available on Disney+ Premiere Access.