Day 7 in Nerdist’s rundown on every Godzilla film to date, and we’re deep in the wonderful nitty-gritty of bizarre 1960s monster action. #7: Invasion of Astro-Monster.

Invasion of Astro-Monster (a.k.a. Godzilla vs. Monster Zero) is largely a rehash of the last film, only with a slightly more bonkers plot. It’s still essentially a battle royale wherein Godzilla, and Rodan team up to fight King Ghidorah, the evil three-headed dragon, but this time it involves Planet X. Yes, that Planet X. I’m not sure if little kids of more recent generations talk about Planet X they way we used to on the playground (i.e., that it’s a possibly-real, possibly-inhabited place somewhere in our solar system, and we just haven’t found it yet), but the mention of it invokes that same blissful childhood fantasy for me.

The human characters this time around are a pair of astronauts (Akira Takarada, star of several Godzilla movies) and a white guy named Glenn (Nick Adams, dubbed into Japanese). They discover a planet named Jupiter, and surmise that it is Planet X. The Xians soon contact Earth, asking to borrow Godzilla and Rodan (!) in exchange for the cure for cancer. The Xians put Godzilla and Rodan (both hibernating) into transport pod and take them to Planet X to fight the monster that forces the Xians to live underground. That monster is, natch, King Ghidorah. Rodan and Godzilla make short work of King Ghidorah, but are left on Planet X.

Godzilla does a victory dance in this film. It’s wonderful.

Eventually, the Xians reveals that they are actually evil, and they wanted Godzilla and Rodan so they could broadcast mind-control signals into their brains and use them to destroy the Earth. They had also been controlling King Ghidorah this whole time as well. Eventually, Godzilla manages to overcome his mind-control programming thanks to Glenn and the human efforts to repel the Xian mind-control machine. Glenn, meanwhile, is upset that his Japanese girlfriend is really an Xian in disguise. I’m now fairly certain a nine-year-old wrote this movie.

This is the sixth film in the Godzilla series, and the series is as strong as ever. Most film series can’t maintain momentum for six films (there are very, very few film series that have great sixth chapters), but these ones seem to be doing just fine. The purity of the monster fights and the inclusion of bonkers alien mayhem has only enhanced the series. Indeed, since Godzilla and Rodan are essentially becoming monster superheroes, we also have something to root for other than the destruction of large cities. Monster fights are why we go to the movies.

An interesting ethical question brought up by Invasion of Astro-Monster: If a monster destroys a planet while under the mind control influence of evil aliens from Planet X, are they ethically responsible for their actions? In this film, the humans manage to interrupt the mind-control signals that control Godzilla, Rodan, and King Ghidorah. Godzilla is exonerated because of his previous actions in repelling King Ghidorah, but doesn’t King Ghidorah get to be re-tried? No. King Ghidorah, even after being freed from the influence of evil aliens, is still considered to be evil. This is a moral gray area.

Sadly, the deliriousness of the series would abate slightly for the next film, and the next few films in the series are a little hit-and-miss, although we are fast approaching the best film in the series. The next Godzilla film is, we will discover, not very good, and was famously featured on an episode of Mystery Science Theater 3000.

Up next: Godzilla vs. The Sea Monster (1966)