If I want a home for aliens like those which invaded in Battle:Los Angeles, what would be the best fitting features?

The aliens:

  • Burn water for fuel (assume they are using deuterium for fusion)

  • Their planet is starving for water (maybe they consumed it? Or it’s not available as a liquid?)

  • Their body mass is a large percent water (or another liquid)

  • They can’t breathe oxygen (so it’s not likely in their atmosphere)

  • they have advanced alloys, meaning very good refining and manufacturing capabilities.

  • Assume they have mastered fusion reactors, lithium is likely abundant.

  • They do NOT use wheels for anything. (So it’s likely not very flat terrain, blindly omitting the possibility that this invasion had specially designed equipment - which it could have)

  • They needed machines to assis them in walking. So they are either: in a liquid environment, or in a low gravity environment. To me, living in a liquid makes technology difficult (unless it’s non conductive?). Legs seem to say it’s not a liquid environment.

  • They have extremely rugged biology with redundant systems. I will interpret that as a sign that predation is rampant throughout the ecosystem; Producers have long been scarce in the food chain.

  • Assume an anaerobic metabolism, possibly in a liquid methane-based biology? Although I don’t think that can co-exist with liquid water?

  • Our ambient earth temperature is tolerable, they don’t likely have a radically hot or cold climate.

There are likely a wide array of planetary environments that could host this species, but

what things can be safely excluded, or are necessarily included in the environment for these aliens?


These aliens are intended to be one civilization in my interstellar conflict, inspired by Rocheworld.

  • I’m a little confused why they seem to be so dependent on water, and possibly they are an aquatic species, yet they have to pillage water. So “water is scarce” and “it’s an aquatic world they destroyed” are wrestling with each other.

  • Hopefully I can come up with a world that doesn’t conflict with this species, and maybe even supports them.

  • $\begingroup$ Note I just corrected “aerobic” to “anaerobic” metabolism - my autospell messed me up! $\endgroup$
    – Vogon Poet
    Nov 1, 2019 at 23:03

1 Answer 1


Your aliens live in a reducing atmosphere.

The atmosphere is methane, ethane and ammonia at temperatures comparable to earth. Water is scarce as you say.

Oxygen is toxic to them. The liquids in their body are a combination of ammonia and long chain alkanes, like hexane. They are very flammable and potentially even explosive in an oxygen atmosphere.

They don't use wheels because they did not invent them.

Because of the toxicity of the oxygen environment they must wear robust exosuits with onboard respirators. The machines to assist with walking are because the exosuits are heavy and it helps to have a power assist; same as a human in bulky power armor. In the buff on their homeworld they walk around fine.

They are superdurable because they are colonial organisms, with a reserve of undifferentiated cells able to flow into wounds and defects and differentiate rapidly to take the place of the damaged organ or appendage. It may or may not have anything to do with predation on the homeworld.

  • 2
    $\begingroup$ In the film they were removed from the suits and did not explode, however I’m not exactly recreating the film aliens. This is good! $\endgroup$
    – Vogon Poet
    Nov 1, 2019 at 23:33

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