The magic of Avengers: Infinity War was how Marvel Studios was able to bring so many different corners of the MCU together. Spider-Man meets Doctor Strange, Captain America and his "Secret Avengers" travel to Wakanda, and the Guardians of the Galaxy stumble upon Thor. As these heroes meet and intertwine for the first time, some go on their own journeys again before coming back together for the final battle. Among those was Thor and his need for not only a new weapon, but specifically a Thanos killing one, and as outlined in the new Avengers: Endgame - The Art of the Movie, a different version almost made it to the big screen.
The alternate version of Thor's journey saw him still accompanied by Rocket and Groot while searching for Stormbreaker. Instead of forging the weapon in Nidavellir, this version saw them traveling to a destination where it already been forged, and previously used to kill something. When the trio arrive on the world of Jormungand, it's buried deep in the skull of "The World Serpent," a creature that hails from Norse mythology like the god of thunder and made its debut in the pages of Marvel Tales #105 back in 1952 (Ten years before Thor!)
"This was going to be the introduction of Stormbreaker," Senior Visual Development Artist Rodnet Fuentebella said. "It was forced way back when, and one of Thor's ancestors had wielded it to destroy the World Serpent. In the top-right image, you can see it buried in the skull of the World Serpent. We wanted to create something that was interesting and different but still feel like you could tell that it's buried in something. There was also an idea of how after the got Stormbreaker, as they were escaping, the children of the World Serpents would attack them and the would have to fight their way out."
The scene wouldn't have been a simple finders-keepers for the god of thunder though, as the children of the World Serpent would attack as he tried to escape with Groot and Rocket, a brief sequence of which can also be seen in the book.
"The mouth parts of this world-eating serpent-worm were actually built around oil-rig drills," Concept Artist Tully Summers says. "They were going for that for a while, and then they thought it was a little too big for an action sequence. And because it was a worm, they wanted more opportunities to storyboard an action fight sequence around it so that's why it got smaller and had articulation and legs and claws to attack and fight and dodge."
As we know, the World Serpent never appeared in Avengers: Infinity War but since we know the character is on Marvel's radar, and an entire sequence was previously constructed, it's possible it could one day pop up in another Thor adjacent project like Thor: Love and Thunder and also Loki.
Avengers: Endgame is now streaming on Disney+ with Avengers: Infinity War debuting on the streaming service on June 25, 2020.
Upcoming Marvel Studios projects include Black Widow on May 1, 2020, The Falcon and The Winter Soldier in Fall of 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, Spider-Man 3 on July 16, 2021, What If…? in Summer 2021, Hawkeye in Fall 2021, Thor: Love and Thunder on November 5, 2021, and Black Panther 2 on May 6, 2022. Marvel Studios has yet to set release dates for its theatrical releases in Ant-Man 3 and Blade or the Disney+ shows consisting of Ms. Marvel, Moon Knight, and She-Hulk.