Now that Captain Marvel has arrived in theaters across the U.S., the entire MCU's future hangs on Avengers: Endgame, coming on Apr. 26. Ever since Avengers: Infinity War came out in 2018, Marvel fans had anxiously awaited Captain Marvel's release in the hopes that she would help reverse the destruction that Thanos caused. With her standalone film now out in the world, theories about how Captain Marvel will play into Avengers: Endgame have officially started circulating around the web in full force. We have just a little less than two months to figure this all out, so here we go. Spoilers ahead!
Some of the theories about how Captain Marvel might influence the next chapter in the Avengers saga get pretty ludicrous, but considering the adage "desperate times call for desperate measures," this may be the perfect time to get creative. So in that spirit, let's dive into one of the most eyebrow-raising predictions for Endgame, which involves none other than Goose the cat.
In the second Captain Marvel post-credits scene, Goose coughs up a hairball onto Fury's desk that turns out to be the Tesseract that he swallowed during the battle. (Infinity War established that the Tesseract held the Space Stone, which Thanos obviously needed, along with five others.) Now, Goose is a Flerken, not a real cat. And in the comics, they can store entire universes inside them. Esquire proposes that Goose could have stored the Tesseract inside a sub-universe, or alternate dimension, which could then allow the Flerken to replicate the Tesseract. Or, perhaps the Avengers — with Captain Marvel's help — will find a way to visit alternate dimensions on their own to retrieve the Tesseract which Goose hid.
Per CBR.com, Flerkens can store different space and time dimensions in their mouths. Perhaps, then, Goose had stored the Tesseract that Thanos eventually stole from Loki in Infinity War. The question, though, is whether or not Goose the cat could transport the Space Stone through time to cough it up like a hairball for the Avengers who survived Thanos' finger snap.
Another intriguing theory is one posited by The Wrap, which requires knowledge of the comic book superhero, Quasar. Quasar's story might hold important information about the quantum realm, which is a huge plot point in Ant-Man and Ant-Man and the Wasp. So here's how that connects to Captain Marvel: According to The Wrap, Quasar received Quantum Bands with access to what one can assume is the MCU's quantum realm from the cosmic entity Eon. When Eon gave these bands to Quasar, the superhero was named the new Protector of the Universe, which used to be a title that Mar-Vell (Annette Bening) held.
Since Captain Marvel could turn out to be Mar-Vell's successor as the Protector of the Universe, she may have also received similar Quantum Bands to Qasar's, which could allow the Avengers to partake in time/space travel in Endgame. Perhaps those Quantum Bands could even solve the mystery of how Ant-Man got out of the quantum realm to show up in the Endgame trailer.
Reddit is rife with theories as well, as you can imagine, and many users have determined that the Tesseract will play an integral role in defeating Thanos in round two. Redditor lotusinthewind theorized, "The team will time travel through the Quantum Realm to different times when the Tesseract was on Earth," which includes the 946 AD, when Odin brought the Tesseract to Earth, the Battle of New York from the first Avengers movie, and the '40s, around the time of the first Captain America movie. A trip to back then might explain why a photo of Peggy (Hayley Atwell) is highlighted in the Endgame trailer.
Another Reddit user, whose username is airbudforMCU, conjectured that one of Captain Marvel's abilities from the comics that wasn't really highlighted in this movie could help the Avengers revive the population that was dusted. That power from the comic books is the ability to absorb energy which would allow her to absorb the Infinity Stones' power. This theory has shown up in multiple posts on Reddit, so it seems that many MCU fans agree that Captain Marvel could prove the missing link to defeating Thanos.
As far-fetched as some of the theories seem, we are in the MCU, and the MCU is in dire straights in the main timeline. Seeing as the first post-credits scene in Captain Marvel shows its the hero surprising Steve (Chris Evans), Natasha (Scarlett Johansson), Bruce (Mark Ruffalo) and Rhodey (Don Cheadle) post-snap, we at least know for sure that Carol Danvers will be in the mix when what's left of the Avengers return.