10 Most Believable Avengers 4 Fan Theories

1. B.A.R.F. Is Key To Time Travel

The Theory

Tony Stark's B.A.R.F. technology - which was introduced in Captain America: Civil War - is going to play a part in undoing Thanos' work, according to one theory. Stark will combine the technology with Scott Lang's knowledge of Quantum Energy (and how it can manipulate time in the Quantum Realm) to create a portal directly into real memories in the past.

Why It's Believable

There's a lot of reasons to believe this one. Firstly, the Russos hinted that B.A.R.F. was going to be key in Avengers 4; secondly, conceprt art from Ant-Man And The Wasp has revealed that the Quantum Realm has a phenomenon called the Nexus that allows anyone to travel through time using their own memories; and thirdly, because the idea of Quantum Energy powering time travel gives Marvel the possibility of closing the time travel loophole for future movies.

If this isn't how it's done - or close to it - it will be a big surprise now.

To read a more comprehensive version of this theory, click here.

Which of these theories do you want to be true? Share your favourites below in the comments thread.