Avengers: Endgame has made a killing at the box office, certainly a welcome sight to the bookkeepers at Disney after the film cost a reported $350 million to make. While a good chunk of that goes to the cast involved with another show, another substantial amount goes to the various visual effects vendors that are tasked with bringing jaw-dropping computer-generated images to life. When it comes to Endgame, one of those pieces of visual effects that were out of this world was the creation of Smart Hulk, the closest thing we'll ever get a massive green Mark Ruffalo.

The effects work on the character was so intense, some Endgame filmmakers said, that it took until the week before they submitted the final copy of the film to the studio. During the director's commentary track on the Avengers: Endgame home media release, co-director Joe Russo revealed it was one of the last things they were waiting on.

"Smart Hulk is one of those characters that we really didn't see in full, until, like, the last week before we delivered the movie because the VFX take so long on a character like that," the filmmaker mentioned. That's when his brother Anthony piped in, giving full credit to Ruffalo's outstanding work on the film.

"We should give credit to Mark Ruffalo, who obviously, is an amazing actor," Anthony said of the fan-favorite actor. "He worked so hard figuring this character out, because, you know he's been playing these two versions. He's been playing Banner. He's been playing Hulk. But sort of figuring out who the combination of them is, was a real journey for him. We did a lot of experimentation. Spent a lot of time on a motion capture stage, playing with different ideas with Mark. And he worked really hard to find this character."

What was your favorite part of Avengers: Endgame? Share your thoughts in the comments below or by tweeting me at @AdamBarnhardt to chat all things MCU! Avengers: Endgame is now available digitally ahead of a home media release on August 13th.

Upcoming Marvel Studios projects include Black Widow on May 1, 2020, The Falcon and The Winter Soldier in fall 2020, The Eternals on November 6, 2020, Shang-Chi and the Legend of the Ten Rings on February 12, 2021, WandaVision in spring 2021, Loki in spring 2021, Doctor Strange in the Multiverse of Madness on May 7, 2021, What If? In summer 2021, Hawkeye in fall 2021, and Thor: Love and Thunder on November 5, 2021