In one of the many montages on the Oscars last night, Brad Pitt explained that he learned his love of cinema from watching a movie in which two "Gargantuas," a good Gargantua and an evil Gargantua, fought each other. "I remember the Brown Gargantua was the good one," he said, "and had to battle the evil green Gargantua, and in the end had to sacrifice himself to stop him." (That decidedly approximate transcription is borrowed from a fansite devoted to Japanese monster movies.) What was he talking about?
The War of the Gargantuas is a late 1960s example of the kaiju genre (kaiju is a Japanese term that roughly translates as "monster"). It starred Russ Tamblyn, aka the leader of the Jets in West Side Story, and was a sequel to Frankenstein Conquers the World (the Gargantuas are, as I understand it, mutant descendants of the Frankenstein monster). Pitt's memory of the film seems fairly accurate: In the film, the brown Gargantua is taken in when young and raised by a scientist, and so he is friendly to humans. The green Gargantua lives at sea, and has no love for humanity; the movie opens "abruptly," according to Wikipedia, with him killing a giant octopus and then devouring the poor occupants of a fishing boat. You can see part of that opening in the American trailer:
IMDb says that the film hit American theaters in 1970, so Pitt was likely about six or seven years old when he saw it. And he is by no means the movie's only fan. The latest installment of the Scooby Doo franchise has apparently paid homage to the film, and the final fight scene in Crank 2 reportedly borrows some of its cuts from the climactic battle of the two Gargantuas—some of which you can watch below.