
One of the villains in Captain America: Brave New World was almost way more disturbing. Among the crowded cast list of the Anthony Mackie-led film was Samuel Sterns' The Leader, played by Tim Blake Nelson from 2008's The Incredible Hulk. However, the villain could've been even more unforgettable if Marvel had kept this terrifying power.
New concept art from Captain America: Brave New World - The Art of the Movie revealed early and wildly horrifying ideas for one of the film's key villains, The Leader. Marvel Studios concept artist Ian Joyner created multiple pieces showing a much more grotesque take on the mutated character, including a horror-inspired power involving a tentacle that could suck out peoples brains, making the villain one of the MCU's most nightmarish to date.

In The Art of the Movie, multiple pieces of artwork show The Leader with a super-enlarged green brain and moving about in a mechanical suit. In discussing his creative process and inspirations, Joyner admitted, "My favorite stuff is creature work," and that “One of my favorite movies is The Thing:"
"My favorite stuff is creature work. One of my favorite movies is 'The Thing.' So whenever I get to play in that world, I have a lot of fun. With these movies, we run a gamut: You're always asking: 'How gross can you really go with this stuff?'"

Joyner was particularly inspired by The Immortal Hulk comic run, where The Leader can absorb not only the intelligence of his victims but also their souls. While he acknowledged "full-on body horror" is something Marvel didn't want to embrace fully, the comic run inspired him to imagine the on-screen villain as someone who could "suck the brains out of other people:"
"We don't necessarily always want to lean into the full-on body horror, but I was delighted with the more recent comic book interpretation of The Leader in 'The Immortal Hulk' run where he literally absorbs people's brains, intelligence, and souls and everything. My idea was, like, could we actually just do something that crazy? I was considering that The Leader might be able to control minds with his brain and even sucking the brains out of other people."

True to Joyner's description, images in the book show an exceptionally grotesque take on The Leader with an Alien-esque tentacle protruding from his brain and threatening Anthony Mackie's hero.

In The Incredible Hulk, Samuel Sterns was a cellular biologist exposed to Bruce Banner's blood. The 2008 film teased Stern's mutation, leaving fans to wonder how the big-brained baddie would ultimately look once transformed. But it wasn't until Tim Blake Nelson's return in Captain America: Brave New World that audiences finally saw The Leader's on-screen design.
During the film, Nelson's The Leader takes revenge on President Thaddeus Ross (Harrison Ford) for having exploited him. But when he's shown on-screen, his deformed cranium, while still gross, isn't as large as it is in the comics (despite that being a plan as shown by makeup tests). It's also far from Joyner's original repulsive, brain-sucking concept, and his idea for the villain to wear a mechanical suit coupled with his towering, green cranium.

Fans can check out Tim Blake Nelson's The Leader and his finalized on-screen design in Captain America: Brave New World on Disney+.
Why Did Captain America 4 Play It Safe with The Leader?
Apparently, The Leader's look was a major topic of discussion throughout the making of Captain America: Brave New World. In fact, Marvel reportedly changed the villain's look during one of the film's reshoots with director Julias Onah (via Variety) explaining they started with "an entirely practical version," before he decided to "push it even further."
Still, achieving that right look was a balance, as Onah explained, since he still wanted "these heightened characters" to fit into the "grounded" nature of Captain America 4:
"You’re making a movie that is more grounded in terms of its visual aesthetic and style, so you want to make sure that even with these heightened characters, it fits into the world of the film. When you think about the arc of his character and the humanity that’s been taken away from him, there’s a monstrosity to him, and I really wanted to lean into that."
Clearly, the concept art of The Leader with that brain-sucking power wouldn't have worked with the tone and style of Captain America: Brave New World. It also would've pushed the film more into the horror genre instead of that of a paranoid thriller. However, it's tough to argue that Ian Joyner's concept would've made Tim Blake Nelson's baddie one of the MCU's more memorable villains, as well as far more monstrous.
Check out what a Captain America 4 writer asked of fans who didn't like the movie here!