Every MCU Event That Might Cause An Incursion (Based On Multiverse Rules)

Phase 4 has already provided multiple events that could have created a multiversal incursion in the MCU, and here is every one of them, based on what has been explained about the multiverse so far. For 21 movies, the Infinity Saga kept the MCU confined to a single timeline. It was not until Avengers: Endgame introduced time travel that the concept of the multiverse and alternate timelines started to wreak havoc on Marvel's infinite gallery of live-action realities, paving the way for the MCU's Multiverse Saga.

Loki, Marvel's What If...?, and Doctor Strange in the Multiverse of Madness have provided additional peeks into the possible disasters that could happen if the multiverse gets out of control. Although villains like Infinity Ultron and Kang the Conqueror haven't brought chaos to the entire multiverse, there are many subtle threats that could. Loki established that seemingly trivial actions could endanger the Sacred Timeline without the TVA's intervention, and now that the Sacred Timeline has been destroyed, the calamities that the Illuminati's Reed Richards describes as the MCU's multiversal incursions seem more likely than ever.

The MCU's multiversal rules haven't been explained in their entirety, but so far, it seems that uncontrolled contact between two universes can damage one of them to the point of total collapse. Taking this into account, there are at least seven interactions between timelines and between universes that haven't been addressed yet and could result in an incursion. Here's every one of them.

Steve Rogers’ Trip to the Past

The first hint at the multiverse in the MCU's 616 universe came in Avengers: Endgame when the Avengers borrowed the Infinity Stones from the past. Following the Ancient One's advice, Steve Rogers went back in time to return the Stones and avoid branching the timeline. However, his decision to stay in the past and live a whole lifetime alongside Peggy Carter went against this principle, and the question of how Steve managed to return to the present remains unanswered. There are no reasonable explanations that don't break the multiversal rules established in Avengers: Endgame, Loki, or Doctor Strange in the Multiverse of Madness, and this could soon become a problem.

If decisions as trivial as being late for work can trigger Nexus events, then living in a different timeline for multiple decades definitely seems like a full-fledged multiversal crime. Perhaps Steve Rogers' trip to the past was part of He Who Remains' careful plan for the Sacred Timeline, but after its destruction, Steve Rogers' actions may affect the past, the present, and the future of at least two timelines, thus triggering an incursion. This potential incursion could bring back Chris Evans' Captain America for future stories, but considering how fitting his farewell was, maybe other Avengers would step up to solve the side effects of Steve Rogers' perfect ending.

2014 Gamora In The Present Day

Another character that Avengers: Endgame's time travel turned into a multiversal outlaw is the Gamora variant who came with Thanos from 2014. Like Steve Rogers, Gamora breaks Avengers: Endgame's time travel rules by staying in a timeline that isn't her own. But in her case, she came from the past and stayed in the present. Gamora's fate after Avengers: Endgame is unknown, but her stay in the MCU's main universe could unleash an incursion, if each timeline is truly incompatible with each other. Although, Gamora could be the least of everyone's worries, as Avengers: Endgame's Thanos came from 2014 with a gigantic army that was soon defeated, and their deaths caused the 2014 timeline to lose not only hundreds of inhabitants, but also major figures such as Nebula, Gamora, and Thanos himself.

Just as Captain America returning the Infinity Stones was pardoned by He Who Remains, the absence of Thanos, Nebula, Gamora, and a few hundred aliens could have been forgiven by the TVA off-screen. But if the Sacred Timeline's destruction means any time-space abnormality now can get out of hand, Gamora's presence could become a threat to the multiverse. After Guardians of the Galaxy Vol. 3 reunites Gamora with Star-Lord and the rest of the Guardians, she could be contacted by Kang the Conqueror, who could take advantage of her situation, or Clea, who could force her to go back to her original timeline in order to avoid an incursion.

Venom's Arrival In The MCU

Tom Holland Spider-Man in the Venom 2 Post-Credits Scene

The dangers of the multiverse were first put into perspective by Spider-Man: No Way Home's multiversal story, where a simple memory-wiping spell resulted in the clash of various different universes. Spider-Man: No Way Home established that none of the multiversal visitors associated with Spider-Man could stay in the MCU's 616 universe for too long, otherwise reality itself would break, as signaled by the rift seen at the end of the movie. Thankfully, every visiting character returned to their home universe, including Eddie Brock. However, Eddie left a drop of symbiote behind in the Spider-Man: No Way Home post-credits scene. This multiversal intruder could be extremely dangerous, as it could be the first and only symbiote in the MCU's main universe.

The longer a multiversal visitor stays in a different universe, the more risk of an incursion there is. Why Venom was allowed to leave a part of him in a universe it doesn't belong to remains a mystery. Perhaps the symbiotes' multiversal hivemind allows them to reproduce in other realities without causing an incursion — allowing Tom Holland's Spider-Man to receive his iconic black suit along the way. But perhaps the rules also apply to symbiotes, and Spider-Man will have to get rid of his own before reality collapses in on itself.

Vulture In Sony's Spider-Man Universe

Michael Keaton as Vulture and Jared Leto as Morbius

A direct consequence of Spider-Man: No Way Home's multiversal story is, surprisingly, Vulture's arrival in Sony's Spider-Man Universe. Despite not having anything to do with Spider-Man's multiversal variants, Vulture was shown to be dragged into the SSU in Morbius' post-credits scene, where Adrian Toomes gets his hands on a new Vulture suit and suggests Michael Morbius to assemble a team. Morbius' post-credits-scene confirms that Vulture was transported by the multiversal rift that was about to introduce every Spider-Man villain into the MCU in Spider-Man: No Way Home, but it doesn't explain why it did the opposite of what it originally intended. Although Adrian Toomes' presence in Morbius' universe doesn't seem to throw the SSU out of balance, it could eventually trigger an incursion. A direct clash between Sony's Spider-Man Universe and the MCU would allow Vulture, Morbius, Kraven, and Venom to meet Tom Holland's Peter Parker, paying off Vulture's vague explanation that his arrival had "something to do with Spider-Man".

All The What If? Broken Realities

Uatu The Watcher in Marvel's What If Multiverse

The first look at an MCU incursion came in Marvel's What If...? episode 4, where a Doctor Strange variant used every trick in the book to keep his Christine Palmer from dying. Unfortunately, Christine's death ended up being an absolute point in time, and despite his efforts, the now-corrupted Supreme Strange's actions caused reality to collapse, leaving him alone in the void until The Watcher recruited him. What's scary is that Supreme Strange's universe may not be the only What If...? universe to go through an incursion, as Ultron damaged multiple realities in his quest for multiversal conquest (including one where he killed Thanos before the Snap). Given that it took Killmonger, Arnim Zola, Supreme Strange, and the Guardians of the Multiverse to stop him, there are now several universes that have been changed drastically. The Watcher also took Black Widow to a new universe after Ultron ravaged her home reality, making her a multiversal castaway that could cause an incursion in her new home.

Scarlet Witch And Doctor Strange’s Darkhold Use In Multiverse of Madness

Scarlet Witch and Zombie Doctor Strange in the Multiverse of Madness

The Illuminati's biggest worry in Doctor Strange in the Multiverse of Madness was the risk of an incursion due to Doctor Strange's use of the Darkhold. According to them, the Doctor Strange of their reality used the Darkhold to Dreamwalk into a multiversal variant, thus triggering an incursion. What they ignored is that Scarlet Witch was already abusing the Darkhold in the 616 universe, which in turn led Doctor Strange to use it to Dreamwalk in Defender Strange's decaying corpse. With no one to keep track of the negative side effects of Doctor Strange and Scarlet Witch's actions, an incursion is now more than certain. Doctor Strange already developed a third eye after using the Darkhold, and Clea recruited him to stop an incoming incursion that may or may not be related to his battle with Scarlet Witch.

Ms. Marvel’s Time Travel

Kamala Khan came in contact with time travel in Ms. Marvel episode 4 when she was transported to 1947. Unlike Avengers: Endgame and Loki's time travel, Kamala Khan's trip to the past doesn't involve alternate timelines. Instead, it consists of a causal loop, where every change to the past is reflected in the present, and each event in the loop seems destined to repeat itself. As tight as this loop seems, it could still threaten the stability of the MCU's space-time continuum, as it is something far too different from anything the TVA, He Who Remains, or The Watcher seem to have dealt with. Considering how different Ms. Marvel's time travel is from Avengers: Endgame's, it could also become a powerful weapon for Kang the Conqueror, who could use it either to cause incursions or to protect himself by creating causal loops where he always has control over every event.