Ghidorah the 3 headed monster is one of the most critical movies in the old Godzilla series. Not only is a new monster introduced, but Godzilla and Rodan go from being villains, to being heroes. The plot involves a meteor hitting the Earth and causing weird weather patterns.  A woman then claims she’s a Martian Princess and warns about Ghidorah destroying the planet. Godzilla and Rodan then appear and begin to fight each other. Ghidorah then comes out og the asteroid and begins to destroy Japan. Mothra is called upon to stop Ghidorah and does so by convincing Godzilla and Rodan to join her and fight Ghidorah. The 2 former enemies of man end up becoming defenders of the Earth.

This is one of my favorite Godzilla movies of all time. It also changed the nature of the series as Godzilla and Rodan were no longer bad guys. They were allies of humans defending earth from Aliens and the monsters they control.