Earlier this week, we ran a guide teasing out which Godzilla and other Toho movies to watch so that you could recognize and appreciate (at least most of) the easter eggs and references in Godzilla: King of the Monsters. Now we're annotating that story to reveal the specific easter eggs and references to which we were alluding, along with some new ones we noticed during a subsequent viewing.

Since the massive radioactive beast first emerged from the sea to decimate Tokyo in 1954, there have been well over 30 movies featuring Godzilla, including 29 live-action flicks produced by Toho, the legendary Japanese studio. Director Michael Dougherty, a lifelong fan, borrows from and alludes to this rich history in liberal doses in Godzilla: King of the Monsters, with some of the older movies providing major plot points and others identifiable only with passing references.

**Spoiler Alert: There are kaiju-sized spoilers for Godzilla: King of the Monsters below**

Along with the original Godzilla and the American reworking that came out two years later (the similarly titled Godzilla, King of the Monsters!), Dougherty told SYFY WIRE that less avid fans should watch Ghidorah, The Three-Headed Monster (1964), because it was the first time that Godzilla, Mothra, Rodan, and King Ghidorah all shared the screen.

It would help fans to also see Mothra (1961) and Mothra vs. Godzilla (1964). The first introduces Mothra and provides crucial background information that comes into play late in Godzilla: King of the Monsters, while the latter marks a major turning point in the franchise. Invasion of Astro-Monster (1965), the second Ghidorah movie, is also crucial.

The References: Though Toho has repeatedly tweaked and in some cases fully rewritten the origin stories for these monsters over and over again, Dougherty's film borrows story points liberally from these movies. In both Ghidorah movies, the three-headed beast is an invader from another planet; in Invasion of Astro-Monster, Ghidorah is mostly known as Monster Zero (and in fact, the U.S. release was titled Monster Zero), as he is known throughout much of Godzilla: King of the Monsters.

This is nothing new, but in Gareth Edwards' 2014 Godzilla, the character Ken Watanabe plays is named Ishiro Serizawa, which serves as a tribute to both the co-creator and most prodigious director of Godzilla movies, Ishiro Honda, as well as the scientist at the center of the 1954 Godzilla, Dr. Serizawa. The tribute is taken further and twisted somewhat in King of the Monsters, when Watanabe's Serizawa sacrifices himself to reawaken Godzilla in order to save the world. In the 1954 film, Serizawa also sacrifices himself, but in that case it was to kill Godzilla and save the world.

In 1954's Godzilla, Serizawa uses a device called an Oxygen Destroyer to take out the kaiju. In King of the Monsters, an Oxygen Destroyer also takes out Godzilla. Fans will notice that the dead fish floating in the ocean after the device is detonated is a direct callback to the way fish flop to the surface when Serizawa tests the Oxygen Destroyer in the 1954 movie.

Oh, and that 1956 American edit comes into play during the credit sequence of King of the Monsters. You have to watch carefully to spot it, when one of the news articles about the kaiju shown on screen bears the byline of "Steve Martin," which is the name of the reporter played by Raymond Burr in the footage added to frame the original film.

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The two Mothra movies — and, frankly, every other Mothra movie after that — also get referenced in King of the Monsters, though those easter eggs are a bit more subtle and not as consequential to the plot. In Dougherty's movie, Ziyi Zhang plays a scientist named Dr. Ilene Chen who seems to have an innate understanding of Mothra. She later reveals that she's a third-generation descendant of women from Infant Island, where Mothra was first found, and the screen flashes photos of two sets of twins, taken in the '60s and '90s, standing in front of a big Mothra egg.

Those are images of the Shobijin, colloquially known as the Mothra fairies. They are tiny magical humans who have a psychic connection with Mothra and accompany her on her journeys. It isn't until late in the movie that we discover that Dr. Chen seems to have a twin sister, named Dr. Ling; they're never explicitly identified as twins, but Zhang plays them both, so we can feel pretty safe in that assumption, I think.

Meanwhile, the 1992 movie Godzilla vs. Mothra (they just switched the names around) was one of several to feature ancient cave paintings that offer some explanation of the monsters' origins. The 2001 flick Godzilla, Mothra and King Ghidorah: Giant Monsters All-Out Attack positions several of the monsters as Earth's ancient guardians, which tracks with Dougherty's new movie as well.

The References: Pretty self-explanatory, but it should be noted that in both those movies Godzilla is the baddie. In Giant Monsters All-Out Attack, Ghidorah is fighting alongside Mothra, which is a role reversal as well. Ghidorah and Mothra definitely don't like one another in King of the Monsters.

In Giant Monsters All-Out Attack, Godzilla roasts Mothra, which provided only a short-lived victory, as the resultant powder (she's a moth, remember?) helps revive Ghidorah, who then continues the battle against Big G. That too is twisted in King of the Monsters, with Mothra's powder helping bring Godzilla back from the brink so that he can deal once and for all with the evil Ghidorah.

Here's another reference I omitted from the original article: In King of the Monsters, Godzilla and Ghidorah throw down in Antarctica, where Ghidorah had been trapped for millions of years. That nods back to 2004's Godzilla: Final Wars, where Godzilla is freed after years living under the ice of the southernmost continent. Once freed, he battles Gigan, who was sent to Antarctica by a race of aliens known as the Xiliens ... who are responsible for sending Ghidorah to earth in Invasion of Astro-Monster.

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The global monster rampages teased in the previews for the new movie hearken back to Destroy All Monsters (1968), which was sort of the Avengers of Toho monster movies at the time, as it set many different kaiju free to romp through different cities and then brought them all together. The spirit of that movie was recreated in 2004's Godzilla: Final Wars, which makes it worthy of checking out as well.

The movie that came after Destroy All Monsters was a clip-heavy flick called All Monsters Attack (1969). It is the only one that stars a child, which makes it quite relevant to King of the Monsters, which focuses on a character named Madison, played by Millie Bobby Brown.

The References: In Destroy All Monsters, most of the earth's kaiju have been brainwashed by aliens to attack those cities; in King of the Monsters, they're manipulated by a device called the ORCA into wreaking havoc across most of the earth's most prominent metropolitan areas. And in both cases, once the monsters come to their senses, they team up against Ghidorah, who is in at least some cahoots with the villains messing with the kaiju. There is also someone holding up a sign that says "Destroy All Monsters" during a protest against the kaiju (like that'll do anything) in King of the Monsters.

As for All Monsters Attack, the child at the center of the story is a latchkey kid who does not have particularly engaged parents. That's not entirely the case with Madison, but her parents are arguably even worse — her dad, played by Kyle Chandler, abandoned her after losing his son (and Madison's older brother) in the 2014 attack, while her mom, played by Vera Farmiga, is secretly plotting to destroy most of mankind.

We won't give away why you should watch them, because they're referenced in the final battle, but Godzilla vs. Mechagodzilla II (1991) and Godzilla vs. Destoroyah (1995) are also recommended viewing.

Rodan is the final giant name-brand Toho monster being introduced in King of the Monsters, and most of its appearances are covered in the movies listed above. That said, you'll also want to watch Rodan (1956), which introduces the character and gives a lot of background information that'll help you better understand that giant flaming bird.

The References: OK, now we can spoil them! One of the great fights in Godzilla vs. Mechagodzilla II takes place at (or all around) Yokohama Park, a baseball stadium in the city of Yokohama, which neighbors Tokyo. The final battle in Godzilla: King of the Monsters is held outside of Fenway Park, where the Boston Red Sox play. Both stadiums take a beating, as you might expect.

When Serizawa revives Godzilla with nuclear power in Godzilla: King of the Monsters, it "works a little too well," as Bradley Whitford's snarky scientist character remarks. It turns Godzilla into a walking atom bomb, with glowing orange-red skin that reflects the growing radiation inside of him. That's lifted directly from Godzilla vs. Destoroyah, the 1995 movie that ended the second generation of Godzilla movies and is generally considered one of the best in franchise history. Big G detonates in that movie, just as he does in King of the Monsters, but their fates are a bit different.

At the end of Rodan, the winged monster falls into a volcano called Mt. Aso and is thought to die when it erupts. In King of the Monsters, it emerges from the same volcano, with wings made of molten lava.

The Post-Credit Scene: Don't worry, we didn't forget that one. The post-credit scene of King of the Monsters finds the eco-terrorist Jonah Alan (played by Charles Dance) purchasing one of Ghidorah's discarded heads. Astute fans will assume he's plotting on creating a version of Mecha-King Ghidorah, a cyborg creature that appears in Godzilla vs. King Ghidorah.

There are likely even more references to other movies — Daugherty packed in things like the presence of a weapon called a Maser, which was seen first in the Toho film War of the Gargantuas and then throughout different Godzilla and kaiju movies, so it'll take many views to decode them all.