The fight on Planet X.
Until recording this off of TCM, the only version of it which I'd ever seen was the edited for time version presented on TNT back in the 90s. I was so ticked off to find out that an entire fight sequence between the three monsters had been edited out in favor of inserting more commercials. Honestly, if they needed more time for commercials, they could have edited out some of the scenes with the human cast. Nobody watched it for that anyway and the plot had enough holes in it that one or two more wouldn't have mattered anyway.
But yeah, it was a real treat getting to see the fight on Planet X for the first time. And with that, I've officially seen the Showa series in its entirety. At least as far as the English dub versions are concerned, anyway.
I'm kind of surprised by the outcome of the fight. I was aware of the victory dance, but I was surprised to see Ghidorah knock Godzilla off of his feet before fleeing. It was almost sort of a victorious defeat. I mean, yeah, he ran away from a fight and therefore lost, but he also knocked Godzilla down as he went. That's probably the only fight in any Godzilla film in which Ghidorah got in the last offensive move. Also, if I'm not mistaken, it's also the only fight to take place in outer space. I don't know about the more recent films, but Godzilla never returned to outer space in the Showa or Heisei series.