Backstory: One space-faring civilization detects evidence of intelligent/sapient life on another planet. They send emissaries. The people on the planet, a species of intelligent apex predators, promptly murder the delegates, take apart, analyze, and start producing crude copies of their ships, and begin prowling the universe as murderous space pirates hunting the other species for sport.

In order to explain why a somewhat less technologically advanced species from a single planet can strike terror into the hearts of a more advanced, more populous people, said alien species has a rather impressive list of abilities, as follows. (I'm being quite detailed here so I can refer back to this post in any further questions about this species, rather than typing it out again, though most of it is pertinent to this question as well, so I would recommend reading it before answering. The specific question is in the last paragraph.)

  1. Great physical prowess: they are extremely fast and strong (fast enough to catch an arrow or deflect bullets, but not the Flash. Strong enough to rip off your arms, but not Superman). Essentially, their skeletal and muscular structures are much stronger and more efficient than Human Joe's.
  2. Enhanced senses: they have excellent senses of smell and hearing (they can track a person like a hunting dog if need be), their eyesight is approximately on par with your average human's, except their night vision, which is vastly superior. They also have the additional sense of heat detection.
  3. Virtually impossible to kill: their bodies heal at an extraordinary rate. Wounds that would be fatal to Human Joe due to blood loss or irreparable damage aren't necessarily fatal to them. The best ways to kill them: Cut off the head (and make sure it stays off long enough for them to die), rapidly destroy such a large portion of the body that it is impossible to regenerate before death ensues, or continue damaging them continuously over a long period of time until they "run out of juice" and can no longer heal themselves.
  4. Shapeshifting. The species can shapeshift, with some limitations. They have to turn into something alive (usually something real they have come into contact with before, though small details beyond what species they choose, such as bone structure or hair/fur color, they can generally use their imagination for as long as it doesn't break the functionality of their basic chosen template). They must stay within a certain margin of size in accordance with their original mass (they can make themselves bigger or smaller to a degree, but only have so much overall mass to stretch or condense). They cannot turn their bodies into non-organic tissue (aka no metal skin. Bone or scales, perhaps, but not metal).
    There are some materials inherent to the species' homeworld that are "compatible" with their shapeshifting, for instance, the hides of certain animals and the fibers of a certain plant. They use these to make clothing and can incorporate them into their bodies when shapeshifting if they desire. There is also a kind of metal that they can change the form of, but not to the extent they can the compatible organic materials. Aka, if you are wearing a leather coat and a metal sword, and turn into some kind of animal, the leather may become part of your animal body, but the metal may not. You can, however, change the sword's form into something more convenient for your shape, such as a metal plate on your back. This metal is very strong, very heavy (by Human Joe's standards), and very expensive due to a difficult mining and forging process. In addition, your ability to affect compatible materials is limited to things you are touching, and to a certain range away from yourself (say, about six inches). So, if you are holding your metal sword, you can reshape the handle and a few inches up the blade away from it, but nothing beyond this. If you are only 3 inches from your sword but not touching it, you cannot alter its form.

The species are fearsome fighters, and in any kind of close quarters battle they can take out large numbers of Human Joe type people. Normal handheld projectile weapons aren't terribly effective against them, as they a) are difficult to hit b) bullets/small projectiles don't usually do enough damage to kill or greatly impair them and c) they tend to close range very rapidly and you only have so long to shoot at them until they are on top of you, especially in cramped quarters like spaceship corridors. I'm not going to go into detail of what kind of weapons people devise to use against them since that isn't the point of this post. I might make another post on this topic later.

Here's the problem: none of their advantages are of much use in space piracy and murder until they are actually on board the other ship and can rampage to their hearts' desire. So, here is my question: You are a murderous, virtually unkillable alien species who wants to go slaughter all the people on another spaceship; given the above described abilities, how do you get off your pirate tub and over onto the poor hapless victim's ship? You don't target only unarmed ships, you welcome the challenge of attacking ships with weapons also, if you think you can get away with it.

I almost didn't post this question for fear it was too subjective, but I think there are only so many possible answers that would actually practically work, since it isn't necessarily easy to board a spaceship against the owner's will, especially an armed one, and I'd like to know if there are any I've overlooked. There may be some options open to these aliens due to their survivability that aren't open to Human Joe.

NOTE: Someone might bring this up, so I'm adding beforehand, they can indeed survive exposed in vacuum for a period of time, though probably not indefinitely.

Edit: In response to some comments, yes, this species does indeed happily attack colonies and slaughter the people on them. I didn't mention it simply because it wasn't part of the issue at hand. They hunt the other intelligent species partly because it is more of a "challenge" than hunting animals, and the more challenging a target you successfully attack, the more "sporting" it is. Ships are harder to attack and locate, which presents a lovely little challenge to our predators.

Some of you are also asking about infiltration or trickery. This is definitely possible, though limited by the fact that most of the predator race don't speak the other race's language. Also, some of these methods would be initially handy, but as the predators gain notoriety and essentially became like the boogeyman, those same methods would become less effective because the victim race would have become wise to them. Other methods, like the distress beacon trap mentioned in one of the comments, would probably still be useful, but harder to pull off.

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    $\begingroup$ "I'm not going to go into detail of what kind of weapons people devise to use against them since that isn't the point of this post. I might make another post on this topic later." Flamethroweeeeer, babyyyy!! Seems like an excellent case for area-denial weapons. Though, a flamethrower in a spaceship isn't probably the smartest idea ever... (Also, welcome to worldbuilding SE) $\endgroup$
    – Nyakouai
    Commented Mar 27, 2019 at 8:41
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    $\begingroup$ I am not sure why they would be interested in boarding ships. They are über predators, why not just find some nice fat colony on a planet without huge defenses and have fun? I mean pretty much all that is dangerous to them is the ship they are on being shot by another ship. I would in their case avoid ship-to-ship action like the plague and go do the fun and easy stuff I evolved to do. $\endgroup$ Commented Mar 27, 2019 at 9:05
  • $\begingroup$ For that matter, if you are a shapeshifter the easy way to board a ship is to wait until it is docked and walk in. So why not just infiltrate or flat out takeover a space port? $\endgroup$ Commented Mar 27, 2019 at 9:07
  • $\begingroup$ Is this happening to a species that knows about points 1-4 plus the will to murder, or is this happening during a time when the targeted species still only knows they lost contact to emissaries they sent to a planet that my contain some kind of possibly sapient lifeforms? $\endgroup$
    – bukwyrm
    Commented Mar 27, 2019 at 9:09

6 Answers 6


From what you've given as abilities, I see two main, easy options:

A) Mimetism

One of your super-predator, (let's call him Bob) took time to study one of the poor human-type Joe (let's call him Joe) before brutally taking him/her/they apart. The next time they meet a Joeys spaceship, Bob goes in front of whatever communication device they have, shapeshift to look like Joe, and act like a very-real-not-alien-Joe™ until the other spaceship accept to dock with Bob's spaceship.

Enter and murder at will.

Caveat: Bob doesn't speak Joey's language? "Our mic is busted, as well as several other critical system, please send help" act could work.

B) Ambush

Along the lines of the precedent caveat, you can rely on the old sci-fi trope of the distress beacon1.

  1. Salvage the distress beacon of a Joey's ship
  2. Integrate it into your own ship
  3. Trigger the distress signal and act dead. Shut down systems, fake minor damages and the like.
  4. Wait for an helpless Joe to come and rescue you. The second he/she/they open the airlock, board the Joey's ship.

Enter and murder at will.

Alternatively, hide a few ships, wait for your prey to try to help the decoy, swarm the Joey's ship. Big(gish) space battles are cinematic.

1: I suppose that Joeys are advanced enough to have distress beacon, if they have spaceships. I also suppose Bobs are crafty, since they learned to make junk-spaceships from wreckage. They also have the nerve (or the stupidity?) to fly them and, IMO, that's extremely badass.

If any Joe read that, I decline all responsibility for casualties on your side, you should be more careful

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    $\begingroup$ One thing to keep in mind would be that the Joes could warn the other Joes of their perils, which could make this method ineffective. Also, +1 for the consistent usage of an unusual naming convention. $\endgroup$ Commented Mar 27, 2019 at 13:03
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    $\begingroup$ @ALambentEye That's the beauty of it. Will the Joeys stop investigating distress beacons cause it might be a Bob's trap? They have to (or not, it highly depends upon their culture). But they will eventually adapt and arm themselves/adopt security protocols to counter this method, indeed. $\endgroup$
    – Nyakouai
    Commented Mar 27, 2019 at 13:14

They developed a number of boarding pods and use them as the armaments of their ships.

Self guided missiles with troops loaded inside that engage enemy ships and penetrate the hull to allow the predators to emerge.

  • $\begingroup$ A fun solution. A friend of mine suggested something similar. Since the predators are pretty hard to kill, they might be up for being wrapped in metal and fired through the prey's hull. Though this approach has it's own share of challenges to overcome, depending on how you do it. $\endgroup$
    – MarielS
    Commented Mar 27, 2019 at 20:06

Perhaps the most effective way would be psychological warfare. If they can bluff their way into letting the defending crew surrender, being taken captive or appear as a crew in need of emergency help they will be aboard the ship and may do as they will.

The only truly safe way of entering a ship is through the airlocks, though it may be rather difficult to dock on a defending ship.

Barring that, one may try to latch on and pierce through the hull of the ship, though this would require an unusual offensive structure as part of the ship, similar to a hollow needle with a seal around it. The needle to penetrate the hull and transfer the attackers, the seal to prevent pressure leakage. The closer the point of entry to control systems, the better. A fine sense of heat could be of use, since I would assume that, unless the ship is autonomous, the largest concentration of personnel would be found in the bridge.

Keep in mind that, unless already inside the ship, your crew will only be able to detect radiated heat, since the vacuum of space cannot transfer heat directly.

It may be noted that larger ships would probably have breach containment systems similar to modern ships, where individual compartments may be isolated to prevent damage. These could also serve as a means of hindering the progression of the infiltrators.

Other than that I would suggest attacking colonies instead of ships, for one since they could be easier to find and for the other since they needn't concern themselves with all this spacey stuff.

I hope this serves as some form of inspiration. You may be able to gather more inspiration by doing some research on invasive species and parasites.

  • $\begingroup$ Attacking colonies would have been my contribution. $\endgroup$
    – Willk
    Commented Mar 27, 2019 at 13:47
  • $\begingroup$ See the edit to my original post :) $\endgroup$
    – MarielS
    Commented Mar 27, 2019 at 20:09

For this answer, I will assume that this species was not artificially created, whether that be by some Creator-deity or a hyper advanced civilization that likes to tinker with genetics. Instead, this answer operates under the assumption that the species evolved naturally, and that every trait it possesses is an evolutionary response to some evolutionary need.

Here's what we know about these predators:

  • They are physically superior in every way
  • They are intelligent enough to recognize advanced technology for what it is and replicate it
  • They are highly capable shape-shifters
  • They are their planet's apex predator
  • They hunt for enjoyment as well as for food

That is an impressive array of abilities! It tells us quite a bit about an individual's capabilities compared to that of the space-faring species you mentioned! But, it also tells us quite a bit about the kind of ecosystem in which they evolved in, as well as their probable hunting methods. So, what exactly do these traits tell us about this species?

Their usual prey is probably more dangerous than any space-faring species they might encounter

If these predators evolved to be as physically strong as durable as they are, then it suggests that their evolutionary path responded to a need for such strength, speed, and durability. This would imply that their prey, or other predators, are considerably more dangerous than those we are familiar with, or else the higher energy needs likely to accompany these traits would not be worth the trade-off. Meaning, whatever we can throw at them, they are likely accustomed to fighting things far more dangerous.

Similarly, their obviously high intelligence would also have evolved as a response to an evolutionary need. Now, intelligence is very useful for planning, avoiding ambushes, using tools, and working as part of a societal group. However, high intelligence is also a heavy drain on the body's resources, as those processes actually require a lot of energy. This means that whatever benefit they gain must outweigh the physical penalties of intelligence. This will not be the case if they are already the biggest, the fastest, the strongest, or the most durable. If that were the case, they wouldn't have a need for intelligence, as it would not help them survive, meaning that there are almost certainly things physically more dangerous than they are, and that a high intelligence (in this case, capable of replicating alien technology) adds a lot to their chances at survival.

All this is to say, they are probably more than capable of not just overpowering, but also outsmarting any space-faring species they come across.

They are probably very convincing shapeshifters

This is an incredibly unusual ability, and again, one that would likely only have evolved if it gave the species a significant edge. As with their physical and mental capabilities, this one suggests a need for advanced camouflage, and even imitation of other species. It is likely that there are other species on their world that live in communities, and that the predators gained a significant advantage from being able to impersonate and possibly infiltrate those communities.

Now, these communities would be far more familiar with these predators than any space-faring civilization could be, and they will likely have developed effective techniques to find and expose impersonators as an evolutionary or societal response. This in turn would drive these predators to become even more effective at impersonating their prey.

Coupled with the species' obviously high intellect, it's not too farfetched to think that they'd be capable of quickly learning to imitate, and even fluently speak, new languages. In fact, I'd consider it more likely than the case where they don't learn languages quickly, because speaking the local language is essential to effectively blending in with any community. With that in mind, and with the information they would probably learn just from inspecting those very first space vessels, it's possible that they can already speak whatever languages those vessels' crews could speak.

In other words, infiltrating a space-faring society is just the next step up for them.

They are social and highly inventive

Building off of some earlier points, this species' high intelligence and apex predator status suggests not only that larger, more dangerous species exist, but that your predators are still the superior predators. Now, this is not a new concept to us. After all, we are Earth's apex predator. We are not faster, or stronger, or more durable than other species, and we would lose a fight against almost any other apex predator... except that we keep inventing new tools and we work together. We have always done so, and now we are the apex species of our planet.

It is easy to imagine that your predator also developed their own tools, societies, and languages. In fact, this is actually necessary, or else they couldn't have possibly replicated the technology they found. So, this species is not just incredibly strong, and capable of planning, but they are capable of inventing and building their own tools, and they have developed their own societies. They are capable of working together and accomplishing things that no individual could accomplish on its own.

Their prey has probably evolved defenses against them

This species is their world's apex predator. This means that every species they prey upon almost certainly has some evolutionary advantage to help them evade this species, or else it would have likely been hunted to extinction. This in turn would drive the predators' evolution, fine-tuning their capabilities, their intellect, and their ability to deceive. Their prey is evolved specifically to defend itself from them, and by definition of being an apex predator, there is nothing on their world able to effectively hunt them.

Compared to that, hunting a species that knows nothing of them and has not evolved any effective defenses against them will likely be easy by comparison, their only disadvantage being the technology gap.

They like to challenge themselves

As you mentioned, this species will be hunting vessels for the challenge rather than by necessity. A species does not hunt for sport or seek to challenge itself unless it is already doing well. And considering the monstrous hell-hole of a world that this species probably evolved on, the idea that they ever hunt for anything beyond necessity is terrifying. This means that, on a world where their prey is big enough, fast enough, durable enough, strong enough, and intelligent enough to require the traits this species possesses, they are skilled enough hunters to hunt for fun!

So how might they hunt in space?

They know their technology is (currently) inferior, so they know they probably can't outrun or overpower an enemy vessel, at least not in a straight-up fight. But they're used to that, so they know better than to try.

Instead, they will probably fall back to the tactics that they developed through millennia of evolution on their home world. Use ambush tactics. Use numbers. But never, ever fight a fair fight! After all, no hunter has ever actually wanted a fair fight!

Here's what I would do, if I were a murderous alien pirate

Space is big. It is unbelievably, incomprehensibly big. This means that, unless I have technology capable of drawing a vessel to me and holding it there (unlikely), then I have to know where my prey will be.

My technology is inferior, so I can't chase them down, outrun them, or overpower them. This means that I cannot let this be a fair fight!

So what do I do?

If they've already been infiltrated, then I will purchase information on my prey from one of our infiltrators. If that information cannot be found, then I will infiltrate them myself to get that information. If possible, I will even join the target's crew, at which point the hunt will practically be over.

If I am able to infiltrate a crew, then all I have to do is wait until the ship is away from civilization, take out the crew (this is probably a smaller ship), and pilot it to a location I have prepared in advance.

If none of that is possible, then I will identify a low-security supply station, research station, or anything else likely to be vulnerable. Then I will watch from a hidden location until I can catch a ship leaving atmosphere. As soon as something vulnerable leaves orbit, I'll intercept it before it picks up speed. This should allow the grapples, or equivalent, to latch the ships together and let me and my crew board.

If I wanted bigger prey...

Well that's a little bit tougher, but it follows much the same principle, the main difference being that I'm bringing friends!

Now, I don't want to destroy their ship; I want to take home a trophy, and an upgrade! So, my ship will have a reinforced hull, with a heavy focus on survivability rather than firepower. As before, I'll have to locate an isolated target, and this one will probably require intel to succeed. So, no intel means no ambush.

Now as before, I need to somehow surprise the target. If I have managed to get agents on board, then I can arrange for them to sabotage key systems at a time when they cannot quickly get help. Otherwise, I have to intercept them at their destination. Should I fail in that, either my prey will escape... or I will be destroyed.

But then, what good is the hunt if there is no challenge?

After that, it's just like with a smaller ship. Weather the incoming fire, attach to the ship, board it, and take it. To sew confusion, smaller vessels will launch and attach to other parts of the target. That way, they will kill too many of their own if they try to purge us, and we will be coming from too many directions for them to mount an effective defense.

They may have reinforced their hulls or added redundant passages (which could be flooded with gas or fire), so our boarding tools will have to be able to puncture deep into the target.

If their passages are short and convoluted, so much the better! This will allow my hunters to close the distance and tear them apart with their hands! But even so, each hunting party will be equipped with a shield behind which my hunters can find reprieve from incoming fire. This can be circumvented with heavy weapons, so my hunters will need ways to communicate with one another so we may surround and divide our enemies.

The defenders may respond by attempting to seal us out of critical locations, or using bulkheads to isolate our hunters! Thus we will need to identify any control terminals or other access nodes that our hunters can use to disable such defenses! As with their heavy weapons, communication will be critical to countering this threat.

With their defensive options accounted for, and with capable hunters more than able to improvise, my hunters will inevitably overwhelm their puny defences! Not only will we have numbers too great for them to overwhelm, but our superior physical and intellectual capabilities, coupled with our understanding of their technologies, will render their ship mine in a matter of minutes!

With the hunt completed, I will either withdraw my hunters along with any captives and choice artifacts or data, or I will have the ship's critical sections sealed from the vacuum and leave with my trophy intact!

And with this treasure trove of information and technology, it will only be a matter of time before I and my hunters can find a way to defeat even their strongest weapons, armor, and tactics!

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    $\begingroup$ Points for the detailed and well thought out answer! Although you do make some additional assumptions based on your estimate of the species' evolutionary environment (not all of which are necessarily entirely wrong). Maybe two deities were sharing a pint one day and one said, "Hey, check out these awesome people I put on this planet," and the other one said, "Oh yeah?" snaps fingers "Well look what I just made? Mine are more awesome in every way! My people could eat yours for breakfast! Y'know what, I think they WILL. Top that, pal." ;) $\endgroup$
    – MarielS
    Commented Mar 27, 2019 at 22:29
  • $\begingroup$ I had actually considered artificial creation lol, but I went with the evolutionary path instead because that is simply a more likely way for them to have developed. That said, a Creator-deity or genetics-tinkering hyper-advanced Creator race would completely invalidate my answer! $\endgroup$ Commented Mar 28, 2019 at 14:24

Disable weapons and engines on the enemy ship and then grapple it.

Then crawl along the grapple line and dig your way into the ship. If you can survive vacuum long enough, you can kill them all while they are fumbling for space suits. Otherwise, you need to drag portable airlocks with you along the grapple lines.

Note that you don't have to disable engines if you out engine the target by a large fraction and your grapple lines are made out of some super material. I can't imagine that this is the case since second hand tech generally is not as good as the original. Especially since the originators will continue innovating while the marauders try to copy what they find.

You also don't have to disable the weapons but that would make the whole process very exciting.

  • $\begingroup$ The main issue with this approach is you need to reliably be able to take out the weapons and engines of the enemy ship. When your weapons and technology are poor copies of theirs, this might not be feasible. $\endgroup$
    – MarielS
    Commented Mar 27, 2019 at 20:07
  • $\begingroup$ @MarielS, I agree. I personally don't think that the Marauder scenario is likely. Maybe they make sacrifices on their ships to overload them with weapons and/or engines. $\endgroup$
    – ShadoCat
    Commented Mar 27, 2019 at 20:42

A couple of people mentioned this method already, but I would like to expand upon it as this has been an idea I had been thinking through for a while.

To get aboard an enemies ship, I envisioned plowing through the hull. the boarding vessel would be equipped with a disposable "docking adapter" that the ship is attached to A 2 piece device. The first part is a spike made of some unbelievably hard material. the second is a ring with plasma fusers to melt the hull.

The boarding vessel rams the target with great speed, piercing the hull. Enough so that the fusing ring is now in contact with the targets hull. The fusing ring is activated and literally melts the adapter into the victims hull. There are shaped charges detonated on the back side of the "spike" that blast chunks of this metal into the inner hull of the ship, blowing away any internal bulkheads that may get in the way and clearing the way for the boarding party to enter through the docking adapter.

These warriors are in pressure suits in case the atmosphere of the entry location is not adequate. They are also equipped with plasma cutters and shaped charges to make t though any further security barriers.

Upon completion of their hunting, they load back into their ship, detach from the docking adapter and simply just space anything left on the victim ship.

This would be launched by the dozens from a larger "mothership" targeting larger victim ships. As the vessels are launched, the mothership pounds away the victim ship's defenses, producing weak spots in the hull, allowing the boarding vessels better chance at punching through the hull. Once one ship punches through, its all over.


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