1. Secret Invasion
The crossover that followed Civil War in the comics, Secret Invasion, has the potential to be a fantastic Marvel Cinematic Universe movie. This storyline chronicled a long-term invasion of Earth by the shape-shifting aliens the Skrulls, who secretly replaced certain superheroes before launching a full-scale bid to conquer the planet. Right now, you could argue that there arent enough heroes in the MCU to pull of a mammoth story like Secret Invasion. But Captain Marvel, Black Panther, Iron Fist, Doctor Strange, The Punisher, Elektra, The Wasp, The Inhumans and Spider-Man are all set to join the universe in Phase 3, meaning that Marvels fourth phase could be perfectly primed for an epic crossover with this much scope. The Avengers, Defenders and Inhumans battling alien copies of themselves that seek to take over the planet via infiltration would be an interesting contrast to the Chitauris all-guns-blazing invasion from The Avengers. Also, no one could trust anyone else after the Skrulls become common knowledge, which would really damage the camaraderie between the MCU heroes. Theres one problem with this awesome idea though Marvel Studios dont own the complete rights to the Skrulls. Since this race of aliens debuted within the pages of the Fantastic Four comics, Marvel would need to strike a deal with Fox before putting the Skrulls in a movie. That seems possible, though, since the last Fantastic Four film flopped so badly. By 2019, Fox could well want to sell or share the property, which would open up doors to a huge Marvel Studios Secret Invasion crossover event. Fingers crossed! Which big crossovers do you want to see in Phase 4? Tell us in the comments