You have to take two separate films and put them in the same universe. You don’t have to use lead characters. How would you do it?
Godzilla attacks New York, but the Ghost Busters and the Statue of Liberty are there to save the day. (Or Cloverfield attacks NY and ‘Zillow and Stay-Puft fight it off.)
CondorMan’s comics help inspire a young Bruce Wayne to build his gadgets. Together they team up to fight The Joker and an army of Soviet Porschses.
The house from the Amityville Horror is where Kevin McAllister is left Home Alone.