A sneaky easter egg in The Incredible Hulk alludes to the existence of Wolverine in the Marvel Cinematic Universe. When The Incredible Hulk came out in 2008, a cinematic crossover between two comic book heroes was just beginning to become a reasonable possibility, but having Wolverine in the same movie universe as Hulk was highly unlikely. While the MCU was laying its foundations to become a decade-spanning franchise full of non-mutant superheroes with The Incredible Hulk and Iron Man, Hugh Jackman's Wolverine was over at Fox, getting prepared to appear in the first installment of his own spinoff trilogy - X-Men Origins: Wolverine - set to be released the following year.

The Incredible Hulk has some important links to other MCU events and some subtle setups for future movies despite being the least interconnected film in the franchise. For instance, the sonic weapons that the military uses to subdue the Hulk are manufactured by Stark Industries, and one of the most distinctive elements the movie sets up is how Hulk is the result of a failed attempt at recreating the Super Soldier Serum that gave Captain America (Chris Evans) his powers. These two connections also come together to slip in a reference to Wolverine and possibly pave the way for his introduction later down the line.

Related: Why MCU Hulk Never Had A True Movie Origin

When Thunderbolt Ross's (William Hurt) motivations to capture the Hulk meet Emil Blonsky's (Tim Roth) hunger for power, the ambitious general provides the soldier with a modified version of the Super Serum formula. A brief look at the canister reveals the details of its fabrication, which include Stark Industries as the producer and Dr. Reinstein as the developer. "Josef Reinstein" is the alias of Dr. Abraham Erskine (Stanley Tucci), the scientist who created the unrepeatable Super Soldier Serum in Captain America: The First Avenger. A more stealthy detail, however, is that the name of the program is labeled "Weapons Plus", which hints at the clandestine program that gave Wolverine his iconic Adamantium skeletal coating.

Weapons Plus and Wolverine in Weapon X

The Weapon Plus program was originally introduced in New X-Men #128 as a collection of all the attempts at recreating new Super Soldiers. It comprises mostly failed projects that range from Weapon I (a.k.a. Captain America's Project Rebirth) to Weapon XVI, and even includes offbeat entries such as Weapon Infinity and the Hulk-Wolverine hybrid Weapon H. However, the most famous one will always be the tenth attempt, or "Weapon X", with Wolverine as its main subject. Weapon X specifically aimed to genetically engineer living weapons. In Wolverine's case, it covered his skeleton with Adamantium and disturbed his mind even further. Other notable subjects related to the program include Deadpool, X-23, and Fantomex.

For The Incredible Hulk, the MCU didn't count with the rights to include any substantial connection to the X-Men, but this tiny reference to Wolverine's origin, as well as the alternate Iron Man post-credits scene that referenced mutants and "radioactive bug bites", managed to give Marvel a glimpse of what its cinematic future could look like. Now, there's no longer any obstacle that impedes the MCU from taking The Incredible Hulk's easter egg as the basis for a faithful adaptation of the Weapon X experiment. This could be a logical approach to Wolverine's highly-anticipated introduction.

Next: Falcon & The Winter Soldier Can Tie Wolverine To Captain America

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