SPOILER WARNING: This article contains major spoilers for Ant-Man and the Wasp, in theaters now.
Ant-Man and the Wasp may have just introduced a major Fantastic Four concept into the Marvel Cinematic Universe -- but not by name. Thanks to some tangled rights issues, Ant-Man's Quantum Void may be the MCU's version of the Negative Zone.
The Negative Zone debuted in Stan Lee and Jack Kirby's Fantastic Four #51 back in 1966. While the Negative Zone isn't a part of the Main Marvel Universe, per se, it is a part of the Marvel Comics Multiverse; that is to say, it's a parallel universe, a dark and largely uninhabited world. Since Mister Fantastic discovered and extensively explored the Negative Zone, it is often associated with the Fantastic Four, but it is also home to major Marvel villains like Annihilus and Blastaar.
As a piece of Fantastic Four mythology, the rights to the Negative Zone belong to Fox -- at least for now. Though Fox and Disney are in the midst of a deal wherein Disney will acquire Fox's entertainment properties, negotiations are far from over. While it looks likely the deal will go through, Disney would not officially have the rights to Fox's properties for another six to 12 months, pushing us into 2019 even at the earliest.
Of course, Disney and Fox have negotiated to trade characters before. Prior to Guardians of the Galaxy Vol. 2, Marvel and Fox reached a surprise agreement: Ego the Living Planet in exchange for permission to change Negasonic Teenage Warhead’s mutant powers from telepathy to explosive abilities in Deadpool. To date, though, Disney and Fox have only swapped characters, not settings. What's more, Ant-Man and the Wasp was written and produced long before the two studios began to negotiate their larger deal, meaning the film definitely would not have had access to the term "Negative Zone."
Notably, Ant-Man and the Wasp director Peyton Reed pitched a Fantastic Four movie to Marvel back in 2003, which means he is familiar with Fantastic Four's history, likely including the Negative Zone. Though he netted the job, he eventually left due to creative differences. Nevertheless, since he was actively working on the project, it's pretty safe to assume he conducted research on the property and learned about the Negative Zone in the process.
So what's a Marvel movie to do if it can't use a setting because it currently belongs to Fox? Well, Ant-Man and the Wasp may have simply slapped a new name on it. Let's take a look at what we know about this so-called Quantum Void so far and what that may mean for future MCU projects, including Captain Marvel.