If the world is coming to an end in 3 years, I hope all the studios get together, burn all the legal papers, fire all the lawyers and give us all these characters to enjoy in a 5 hour long movie:
Avengers, Spiderman, X-Men, War Machine, Black Panther, Dr. Strange, GOTG, Justice League, Indiana Jones, Blade, Daredevil, FF4, Muppets, Rocky, Rambo, Hobbits, Gandalf, Star Wars, Godzilla, Conan
vs
Terminators, Predators, Aliens, Galactus, Thanos, Sinister 6, Nazis, Red Skull, Brotherhood of Mutants, Sentinels, Joker, Smaug, Brainiac, Doomsday, Darkseid, Jason, Michael Myers, MechaGodzilla, King Ghidra, Sauron, Zombies, Loki
Don't care about the story, don't even write a story, just start the movie with everyone fighting and stay on them fighting for 5 hours.