Generic Space Opera Bestiary: Space Crabs!

 

Have you heard of “Carcinization?” The tendency of nature to evolve things into crabs” – XKCD

Of course, carcinization is more than just a meme designed to give us memes of crabs rocking out to sweet techno: it represents a very real trend in nature, and if it happens on earth, it’s highly plausible that we’ll find crabs in space too, but sheer Darwinian pressure. 

This isn't the sort of thing that I imagine players will really want to see as background elements, nor are they an especially visible part of our food chain (though we totally eat crabs). Players may well expect to fight crab-monsters.  I will note that when hunting for some pic to steal and toss up on the side of this post, I ran into the problem that crabs already look pretty alien, so it's hard to explain to players why a particular crab species is totally from another world (Green and purple, I guess), but I'm pretty sure if you describe a literal japanese spider crab trundling down the beach, they'd already think they were on another world.  So I'm mostly writing this one for the memes.

 

Space Crabs in GURPS Space

When it comes to Terrain, wikipedia states that they are found in “all the world’s oceans, as well as in fresh water and on land” which probably means we’re talking Island/Beach, with Reefs, Banks, and River/Stream, tropical lagoons, etc and I wouldn’t be surprised to find variants around deep vents either. But I think we’re not going to see them penetrate especially far from the water, as they ultimately seem an amphibious sort of creature (though scorpions, if you squint, start to resemble “desert crabs.”). They’re walkers, of course, but there are some who can swim and they show some aptitude at burrowing.

They are typically omnivores, though I suspect, like with rats, there’s a lot of scavenger behavior from them, just not exclusively.

When it comes to Size, “(crabs) vary in size from the pea crab, a few millimeters across, to the Japanese spider crab, with a leg span up to 4 (meters).” But the way I tend to picture a “generic crab” would be just a bit bigger than a rat, so let’s treat them as SM -5 and 1 lb, which gives them ST 2.

Crabs, like most everything else we’ve discussed, have bilateral symmetry, with oh so many limbs: typically 5 limbs per side (which is possible on a roll of a 4). The scientific name of crabs, Brachyura, is a reference to them having a short tail, but they have such a short tail that I think its safe for us to ignore it. They certainly have manipulators, but GURPS Space either doesn’t understand what “bad grip” is, or lacks the tools to describe the pincer of a crab: these typically have what GURPS Template Toolkits 2: the Closest You’ll Actually Get To GURPS Bestiary 4e Races would call “Good Grip + Hamfisted” and this features in the Cancroid morphology metatrait from the same book. Finally, they have an exoskeleton.

How much Exoskeleton? Well, looking at Skin, we expect an average result of Tough Exoskeleton, but I think Heavy Exoskeleton is reasonable, especially given how tank-like they’re famous for being. But given their amphibious nature, it’s worth talking about how they breathe which is, from what I can gather, exclusively through gills, but they can even breath with their gills on land as long as those gills stay moist? For temperature, I’d treat them as cold blooded, and they molt.

When it comes to Sex, crabs have two sexes and engage in internal fertilization, which means they do the nasty as you and I would recognize it, rather than spawning. This makes them egg-layers. I’m not clear on their exact strategy, but I would guess an unloving Strong-R strategy.

When it comes to Senses, I have a very hard time finding information, and often find myself stumbling across scientific papers, so this seems to be something that’s not that well understood. As best as I can tell, they have Bad Vision and 360° Vision (I don’t know about colorblindness, though I did find a reference to one crab species capable of UV vision). They can hear, though it seems anthropods might have Hard of Hearing? I’m not sure. I can’t find much on crab sense of touch, but there is debate as to whether anthropods can even feel pain, and some articles I found that they have fine hairs that improve their sense of touch. I don’t know, man. They do seem to have a good set of chemoreceptors in their antennae, which suggests that they have a sense of smell, at least.

I’m a little torn in crab intelligence. On the one hand, I see lots of articles that talk about their complex social behavior, but on the other hand, this seems meant in the patronizing sort of way we talk about the complex behavior or ants or bees, so it seems they’re likely IQ 1 (which GURPS Space would find quite likely). They would likely engage in Mating Only and be Solitary creatures.

This gives them a generic Psychological Profile of Chauvinism -1 (Broadminded; -3 if we treat them as scavengers), Concentration 0, Curiosity 0, Egoism +0, Empathy -1 (Oblivious; -2 if we treat them as scavengers), Gregariousness -1 (Uncongenial; -2 if we treat them as scavengers), Imagination 0 and Suspicion +2 (Fearfulness 1).

Generic Alien Crab Stats

This is one of those where I have to struggle to find stats on my own. We established crabs at ST 2 somewhat arbitrarily. You can certainly go much weaker. For DX… I don’t know, let’s nail it down to a slightly awkward 9. Let’s give them an insectile IQ of 1, but a pretty tough HT, as they seem to “eat anything” like rats do. For basic move, I’ve found numbers all over the map from 1 to 5, but let’s make them about 4. Given the debate around their senses, I think it’s fair to assume they have a weak sense of perception. For Will, on the one hand they seem to have a skittish disposition, but on the other hand, have a reputation for stubbornness and fighting when others would flee.

ST: 2	Basic Speed: 5.25	SM: -5
DX: 9	Basic Move: 4
IQ: 1	Perception: 9
HT: 12	Will: 10	DR: 3

Traits: 360° Vision; Acute Smell +3; Bad Sight; Cancroid; Cold-Blooded; Doesn’t Breath (Air-Breathing Gills); Pressure Support 1; Reduced Consumption (Iron Stomach) 3; Sharp Claws; Wild Animal.

Pincer (9): 1d-6 cutting, Reach C

Variations

Deep Crab

Crabs often move from land to sea, and do so by walking, and may reach considerable depths. In fact, we can find crabs at extremely low depths, but they tend to be bone-white and blind, because the depths are so brutally dark, and they’re often bound there by adapting their biology to those temperatures. The problem, though, is that PCs would never see such crabs. It is plausible, though, that there are crabs with the ability to transition from fairly extreme depths. I gave pressure support to the standard crab because I’m pretty sure you can drag it up from a pretty low depth without killing it (but I could be wrong). Whatever mechanism allows that might allow even deeper depths, and at least one crab species from the depths had UV Vision (as mentioned in the Fish post, UV light penetrates deeper into the water than normal light does). Many crabs I found discussed in the depth and a different orientation of for their legs that allowed them to walk forward. I don’t know if this would have any change on their stats.

Lens (Deep Crab): Pressure Support 2; UV Vision

Giant crabs

The Japanese Spider Crab gets up to four meters across, which puts it at SM +2. However, this is mostly just extremely long legs. The actual mass doesn’t get much heavier than 40 lbs (closer to SM -2) For reference, American lobsters get up to this size. If we compromise towards something arbitrarily large, we might settle on SM -1, 80 lbs which gives us an ST of 9. This doesn’t really impact their speed (Japanese Spider Crabs are quite slow).

Lens (Giant Crab): SM -1; ST 9.

Pincer (9): 1d-3 cutting, Reach C

Murder crabs

Crabs have a reputation for being a dangerous animal. That’s hardly surprising, given those claws and their bad attitudes. But just how dangerous could we make them? Of course, this is a Space Opera bestiary, so we could make them arbitrarily dangerous, but GURPS Space does suggest that some animals could integrate kevlar-like material (especially “spider-silk” like material, and both spiders and crabs are a type of anthropod). I’ve read some stories, though I struggle to find references, of animals integrating metals into their pincers (some ants seem to do this) or their exoskeletons for additional defense, so an exceptionally high DR is not completely implausible. This might justify a (measly) DR 12 (on par with a concealable vest, though realistically that might be DR 12/5) and increased damage from their pincers. If we add something like the pistol shrimp’s claw, or a fiddler crab’s extreme claw, we might justify some considerable striking ST as well.

Taken together, we might get a claw that deals 1d-1 cutting damage, which averages 2-3 damage, which is pretty spectacular! On a giant crab, we’re looking at 1d+2 cutting damage. This is a pretty cinematic critter, but it should be noted that it doesn’t even rate as a proper space monster, though an unarmored civilian would certainly find a Giant Murder Crab to a be a serious threat, especially since small sidearms wouldn’t phase it!

Lens (Murder Crab): DR 12; Striking ST +5 (Claws only); increase claw damage by +2.

Pincer (9): 1d-1 cutting, Reach C

The Spherical Crab

Okay, you can’t do a spherical crab. The point of a crab, is that it has legs and claws, and you can’t arrange those in such a way that it doesn’t have top/down asymmetries. We can, however, do radial symmetry. Let us imagine a trilateral creature: it has three sides, and each side has one leg and one claw. It balances, then, on three legs,and it has three eyes pointed out in three directions. Instead of a fully armored claw, let’s imagine a hardened claw on the tip of a tentacle that can be retracted in, allowing it to flex its arm in multiple directions. Its mouth would be on top, and its anus below. It might lack the ability to breed in the traditional way, so might return to more of a spawning strategy, but this can hardly make the animal stupider.

ST: 2	Basic Speed: 5.25	SM: -5
DX: 9	Basic Move: 3
IQ: 1	Perception: 9
HT: 12	Will: 10	DR: 3

Traits: 360° Vision, Acute Smell +3; Bad Sight; Cold-Blooded; Doesn’t Breath (Air-Breathing Gills); Extra Arms (3 Arms, extra-flexible, retractable); Extra Legs (3 legs); Good Grip 1; Hamfisted 2; Pressure Support 1; Reduced Consumption (Iron Stomach) 3; Sharp Claws; Wild Animal.

Pincer (9): 1d-6 cutting, Reach C