For the sequel to 2016's Doctor Strange, Marvel Studios took Benedict Cumberbatch's sorcerer into the multiverse as part of a story where the Scarlet Witch (Elizabeth Olsen) attempted to invade a new universe where she could be with her kids. This could only be done by obtaining the powers of America Chavez (Xochitl Gomez), who can travel the multiverse at will thanks to her star-shaped portals. This allowed Multiverse of Madness to show glimpses of nearly two dozen universes, even though the movie primarily takes place in only three of them. The multiverse exploration allowed the MCU to establish the concept better and tease the future, as Multiverse of Madness includes the first-ever mention of incursions.

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With the MCU's potential Multiverse Saga just beginning to unfold, incursions will be a crucial multiverse concept moving forward. Doctor Strange in the Multiverse of Madness briefly explains the idea, but the comics bring additional insight into what they are and what they might mean for the future—like Secret Wars. Here's a breakdown of incursions, their meaning in the multiverse, and what Multiverse of Madness' ending mention of them could reveal about the future.

How Doctor Strange 2 Defines Incursions

There are multiple mentions of incursions during Doctor Strange in the Multiverse of Madness. It begins with The Illuminati arresting Doctor Strange on Earth-838. The superteam reveals that they are assembled to protect their universe from various threats, including multiversal incursions. An incursion is defined in the MCU as an event where two universes crash into one another. The Illuminati detail that they have dealt with incursions before, as Earth-838's Doctor Strange triggered this multiverse event after using the Darkhold to try and learn how to defeat Thanos. Strange's interference with the world by dream walking resulted in the complete destruction of that universe, making him responsible for killing trillions. For that reason, Multiverse of Madness' Illuminati team killed Doctor Strange after Thanos was defeated.

It is so far not explained what triggers an incursion in the MCU, even though Doctor Strange in the Multiverse of Madness' post-credits scene sets up another one. Doctor Strange is greeted in the streets of New York by Clea (Charlize Theron), a powerful sorceress from the Dark Dimension, and learns that his recent actions have started another incursion. Based on Clea's request for Doctor Strange to help her stop the incursion from happening, the MCU indicates there is a way to prevent the two realities from collapsing on top of each other and destroying one or both universes. Doctor Strange 2's post-credits leave some big questions for the MCU to answer moving forward, including what starts an incursion and how someone can stop it.

Marvel Comics’ Incursions Explained

The concept of incursions is relatively new in the Marvel Comics universe. Writer Jonathan Hickman created incursions as part of his planned Secret Wars reboot and helped reboot the multiverse. The comics explain that incursions are the result of the multiverse timeline contracting. Just like in the MCU, the Marvel universe includes infinite universes with infinite Earths and infinite outcomes. However, each universe has the same fate in the grand scheme of the multiverse: death and destruction. The complexity of the multiverse timeline means that all of these universes are connected somehow, including when they are created and destroyed. In the lead-up to Jonathan Hickman's Secret Wars, it is revealed that one universe was destroyed prematurely several years ago thanks to the Fantastic Four villain Molecule Man.

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Once the first universe dies, there is a chain reaction through the multiverse that sees different universes die exponentially. When two universes collide, Earth is the collision point in all instances. This provides an eight-hour window in the comics, known as the incursion, where the different Earths are temporarily within view of the other. There are many possible ways to stop an incursion in the comics, such as destroying one Earth, which saves both universes and one Earth from total destruction. The Avengers once used the Infinity Gauntlet to force an approaching Earth away, although this resulted in the destruction of multiple Infinity Stones. If the incursion is not stopped during the eight-hour window, both universes are destroyed, contracting the multiverse timeline even more and setting more incursions into motion.

Doctor Strange 2’s Incursions Set Up Secret Wars

The introduction of incursions in Doctor Strange in the Multiverse of Madness is another massive indicator that the MCU is planning a Secret Wars movie. Initially conceived by Jim Shooter in the 1980s, Jonathan Hickman put a new twist on Secret Wars in 2015. Thanks to the multiple universes occupying Marvel's comics, the reboot was designed to simplify the multiverse, eliminate several universes, and merge the comics into a single continuity. It all led to an incursion between the main Marvel comic universe (Earth-616) and the Ultimate Universe (Earth-1610) and the convergence of multiple universes on Battleworld. The MCU's multiverse has only started to be explored, but the mention of incursions in Doctor Strange 2 directly teases their unconfirmed plans for a Secret Wars movie.

With multiple mentions of the multiverse threat in Multiverse of Madness, it is quite clear that Marvel Studios wants audiences to become familiar with the idea of incursions. The MCU's potential Secret Wars movie could be the ultimate crossover for Marvel on the big screen. Instead of just being a crossover of MCU heroes, the idea of different universes colliding could bring Fox's X-Men franchise, Sony's Venom-verse, and any other past non-MCU Marvel movie together. While Spider-Man: No Way Home teased audiences with the three live-action Spider-Men together, Secret Wars could bring Hugh Jackman's Wolverine, Tobey Maguire's Spider-Man, Tom Hardy's Venom, Chris Evans' Human Torch, Nicolas Cage's Ghost Rider, and many others to the MCU - either showing their universes/franchises being destroyed or having them unite with MCU heroes on Battleworld.

When Is The MCU’s Secret Wars Movie Happening?

As Marvel Studios builds up its multiverse storytelling in Phase 4, it should only be a matter of time before a Secret Wars movie happens. The creative team behind Avengers: Infinity War and Avengers: Endgame - writers Christopher Markus and Stephen McFeely and directors Anthony and Joe Russo - have already expressed their interest in making the epic crossover movie. So far, Marvel Studios has not confirmed plans for a Secret Wars film. There's an argument that this could be the MCU's next major two-part event film, a culmination of another decade of storytelling that also encomes decades of Marvel movie history beyond what Marvel Studios accomplished. If that is the case, Secret Wars might not happen until closer to 2030.

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Then again, Marvel could scale down the event and have Secret Wars act as Avengers 5 and the conclusion of Phase 4 or Phase 5 - and the multiverse itself. This would allow the MCU to streamline its multiverse story and potentially become shortcuts for introducing the X-Men, Inhumans, Fantastic Four, and other significant concepts. It could even possibly sort out Spider-Man's movie future, where Tom Holland's Spider-Man could leave the MCU for Sony's Spider-Man Universe or officially merge the cinematic universes. Marvel Studios making Secret Wars as Avengers 5 could mean audiences get to see it by 2025 or 2026, just a few years after Doctor Strange in the Multiverse of Madness' incursions mention really set the stage for the event.

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