So in my fictional post-apocalyptic world there are Godzilla sized monsters that were powerful enough to destroy humanity. They are powerful but not too overpowered, for example, most of them can take down a military convoy with no problems, but they cant beat an entire military by themselves. What kinds of traits would allow them to usher in an apocalypse? My requirements are that they are Godzilla sized and there are multiple variants of them.

  • $\begingroup$ Fire-breath, sonic attacks, poison, radioactivity, ability to shoot projectiles out of their bodies, flight, invisibility, resistance to most attacks, regeneration ability, ability to cause earthquakes, cloning, ability to summon smaller monsters, etc. The problem with this question is that there are too many possible answers. I think you need a little more context. What do the monsters look like, are they giant lizards like Godzilla is? What is their origin? Are they magical or made by technology? More importantly, what is their limit? What aren't you looking for? $\endgroup$ Feb 13, 2022 at 16:32
  • $\begingroup$ If they were made in a lab, then the answers need to be a little more grounded in reality. If by magic, then the answers will be a little more free-flowing. If the monsters are some sort of lizard-beasts like Godzilla, perhaps they can have some sort of breath weapons such as fire or ice. If they have a weakness to fire, then ice-based attacks make more sense. $\endgroup$ Feb 13, 2022 at 16:39
  • $\begingroup$ An alien nemesis with the capability to create teleport 100 Kaiju could also teleport smallpox or other biological agents into 100 cities. Or smash an asteroid into Earth. Or nuke a couple carefully chosen capital cities. Or cause an apocalypse dozens of interesting ways. So I would gloss past the logic and explanations and consequences unless you plan to spend pages and pages closing each hole (boring). Just declare "it happened" and get to the big-monster-fights with whatever characteristics you want each monster to have. $\endgroup$
    – user535733
    Feb 13, 2022 at 16:52
  • $\begingroup$ @thequestioner I have a tip for you, that may salvage your question: suppose you would describe your monster some more.. you have to design it.. then ask us how many of them you would need to cause an apocalypse. $\endgroup$
    – Goodies
    Feb 13, 2022 at 19:43
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    $\begingroup$ If they come from a universe where antimatter is dominant over matter than they don't have to be very powerful at all. :D $\endgroup$ Feb 14, 2022 at 13:19

3 Answers 3


I am Cubes Law, Esq. My job is to make questions about giant creatures in the and boring because reality does not work that way.

There are some creatures in real life that are kaiju-sized. They are all clonal forests, fungi or colonial organisms. If they were vertebrates, they would be made almost completely of leg bone just to support their immense size. They would have such a slow metabolism that they would be unable to walk and since synapses do not work at light speed, they would take minutes to hours to react to any stimuli. Any military would thus be able to easily dispatch them.

The only aggression such a kaiju might be able to do is by arriving on Earth from space. Your hundred kaijus would need to collectively deliver as much kinetic whoomp as the dino killing asteroid. A bit of googling and $E = \frac{mv^2}{2}$ are your friends here. Short of that your kaijus will just be target practice and possibly a one-time source for some delicious bone broth.

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    $\begingroup$ +1, I can add with only 100 of them, their size would even have to be considerably larger than a Kaiju ! Estimate the Dutch Navy could take down 100 Godzilla's in 2 days. Even King Kong could do the job. $\endgroup$
    – Goodies
    Feb 13, 2022 at 22:40

Only with indirect means and ingenuity


Movies often show that these creatures are unable to be detected at times. The reason for this is simple. Human armies pack an incredible punch. Even without nuclear weapons humans can destroy large areas with powerful bombs. If these creatures were detected from a distance, they would be pound to dust by precision rockets and really big bombs. Think you can protect yourself in the water? Explosions in the water have a much smaller range, but anything in that range will receive much more of the destructive power. To have any possibility to stay alive. When they attack cities however they near certainly need to expose themselves.

Anti electronics

Besides camouflage they need to hamper the military. So much is electronic these days. Have an EMP to turn much if the military off! Problem solved? Not quite. Though it removes a lot of the arsenal, many weapons were and still are mechanical. There's still some of the bigger weapons around, possibly some with the intention to circumvent an electromagnetic attack from an enemy. In addition many can be reconfigured to be fully mechanical. They probably will be ok killing millions to save many more people quickly enough.

This is damning. In any direct attack scenario such creatures would lose and likely lose big. They need to cause the apocalypse another way. That is why square qube and willik suggested some excellent alternative answers. Below my own.

Attack indirectly

The apocalypse doesn't need to be quick. It can take a few years or even decades. We're very dependent on nature for many things, so let's destroy the ecosystem or something instrumental. Let the creatures expell enormous amounts of methane or similar to accelerate the heating of the Earth. This is still highly dangerous, as they can be tracked via such emissions.

CFK was was a gas used in many spray cans. They quickly found out it was a horrible idea, as it destroyed the ozone. Have the creatures normal food processing emit such gasses, destroying the ozone and leaving the Earth to dangerous radiation.

Many (if not all) ecosystems eventually depend on sea life. Attack this by eating a lot of it. The waste these creatures make can pollute large amounts of water. If done strategically this can remove large areas where life thrives.

It can also attack the humans more directly by messing with their stuff, like destroying deep sea cables, EMP a city or eating crops and retreating. The result will hopefully let society tear itself apart.

Lastly you can use diplomacy. Have each kaiju fulfill a different role in an intelligent society that can talk to the humans. With such large creatures you can add big brains, which can be used to convince humans to have a symbiosis. Eventually they will use technology or society to fulfil their purpose.


How to measure power of a kaiju? GUs? Is there some standardizaton?

How about this

  1. Kaiju show up.

2. Humanity goes overboard and we destroy each other.

This is plausible. Countries are destabilized by the kaiju and regimes change. Regimes not destabilized mount disproportionate responses. Scared humans fight each other. Apocalypse ensues.

This was done well in World War Z the book (which I recommend). Zombies triggered a nuclear war between Iran and Pakistan. This could work for your scenario too - military responses to the kaiju and against other countries are the apocalypse. Then your kaiju can otherwise be what works best for the present in your fiction.


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