Godzillas 1: Marvel Comics Godzilla

The year is 1977, and Godzilla was on a seeming hiatus since 1975's "Terror of MechaGodzilla." Toho signed a deal with Marvel comics to make a series based on their most famous Mon-star. So for about 2 years and five months, Godzilla was pretty much a part of the Marvel Universe. He was approached in a way similar to the Hulk, a massively destructive creature being relentlessly pursued by the Government despite the fact that he's capable of heroics and saving the world despite the amount of carnage and chaos he creates.

At first most of his opponents consisted of giant monsters, as well as the giant Japanese robot Red Ronin, but near the end of his comic's run, he'd come into conflict with various Marvel heroes, including the Fantastic Four, the Avengers, and Hercules' short-lived group The Champions. Needless to say, Godzilla proved to be quite an unstoppable force, even for these superhumans.

But apparently poor sales cancelled the series in 1979, and thus Godzilla faded into Marvel History.

Rumor has it, Toho wasn't exactly thrilled about the idea of Godzilla interacting with Marvel's superheroes AT ALL.