Last year, a grey 'Savage Hulk' Funko action figure was introduced as a Hot Topic exclusive for the Avengers: Age of Ultron, and it had many fans speculating that this latest Marvel sequel would actually introduce the idea of a Grey Hulk on the big screen. If you saw the movie this weekend, you know that doesn't happen. But a new FX video for the movie reveals that it almost did.

Mike Seymour of Wired sat down with the men behind the special effects of Avengers: Age of Ultron. The resulting video gives a pretty in-depth look at how the already iconic Hulk vs Hulkbuster scene came to be a reality. While discussing the epic fight scene, and Mark Ruffalo's motion-capture performance as the Green Goliath, they reveal that director Joss Whedon and his team wanted a grey Hulk when Scarlet Witch takes control of his mind. But the green Hulk proved to be way more popular, so that is what remained in the movie. ILM reveals:

"Initially Hulk was planned to turn grey when he is angry Hulk in the Hulkbuster sequence. But everyone wanted the green guy. In the end, ILM just changed his eyes to make him look more sullen when he is under the control of Scarlet Witch."

The epic Hulk vs Hulkbuster scene is finally on display in movie theaters around the globe this weekend. The fight scene, which serves as the main action centerpiece in this mammoth blockbuster, has already helped push the film to a global box office total of more than $400 million. If you've already seen the movie, now you can take a look at how it all came together. Maybe we'll see Grey Hulk in a future Marvel movie?