How high up in the Kardashev scale would a civilization need to be to neutralize, if not kill...

Wouldnt it suffer a gravitational collapse with ao much mass?

To have it stuffed and mounted, of course.

Depends on how easy this fictional creature of yours is to kill.

If a single missile in the weak spot will do it, then the civ will not need to be very advanced.

Fuck you guys! No seriously, fuck you!

The fuck kinda gall do you have to be on the fucking internet and can't fucking google something. Go be retarded somewhere else you fucking retarded faggots.

That said though, consider this: human-sized life is probably the sweet spot for emergence of sapience. We have two constraints:
1. The complexity of the neural system;
2. The amount of evolution necessary for that system to be sapient, and not just extremely complex.

Something very huge (and thus with a greater lifespan) would witness less volume of experimentation over time. Something very small (with a shorter lifespan) would witness a lot of experimentation, but is not complex enough.

It would be a black matter ir an hidrogen monster. There isnt enough hrvier matter for anything else at least yet

Define "monster". Because it's hard to see how a single entity on such a scale could exist.

What's an Internet?

If its an eldeitch abomination the civ is fucked, best hope it doesn't notice them. I would imagine the civilization would need to be incredibly advanced (2 steps below the beast's size) to even realize it's alive and not just a physical phenomenon or force of nature. If the creature is just a living thing passively doing as it does then the civ would have to be at least one step above the beast's size and capable of coordinating and moving fast enough to try to set up some kind or offensive. The massive distances and amounts of matter and energy involved would be impossible to acquire and replenish while still keeping civilization running otherwise unless they have reality bending tech, at which point they might as well be the monster.

At least a Type-III on the vanilla Kardashev.
If we're adding in additional scales like the Barrow-Kardashev, you would need at least a Type-II-minus.

Tier 0 like us. If you are small enough monster can't do anything to you. And if we are pesky and civilizations like us are plentiful enough we can kill the monster from inside like virus or bacteria.

If it hasn't collapsed into a black hole already then it also has the density of a supercluster. The civilisation in question can just live inside of it, no reason to kill anything.

Got you senpai
>you
>are
>an
>asshole

Most big things generally tend to be quite difficult to kill. The Cretaceous period was defined by an arms race between herbivores either getting more armoured or fucking HUEG, and carnivored developing bigger and bigger jaws and more powerful crushing bites to be able to actually take monsters the size of houses down.
Back to OP
First, superclusters aren't of any sort of discrete size, it's a general term for an area where there are lots of galaxies, with no observable mathematical trend, just what sort of fits. Maybe they're defined by dark matter pillars or cosmic brines, but we don't know. So a supercluster size creature could cover about three orders of magnitude.
The first thing you'd have to ask is what the fuck it eats, and what it spends its time doing. It would contain most of the mass in the observable universe regardless of density at that scale, unless it was really a creature the size of a large planet, with the ability to manipulate electromagnetic and gravitational forces over an area the size of a supercluster.
Essentially, conventional logic, biology, and physics do not apply to this thing, so the term "space monster" is meaningless. How do we even know it's alive? Can it reproduce? Why would we not assume it's a natural phenomenon, and leave it be? How would it threaten a civilization?
OP is far, far too vague to be able to extrapolate even vaguely enough information to understand the problem at hand, or if there even is one.
But if you mean a giant space worm that's somehow the size of a supercluster then probably 1-2, to create a few nicol-dyson beams, which might kill it in a very long time, or 2-3, to create a galactic nicol-dyson.
But who knows, maybe we'll have gravity pulse accelerators by then or something.

I wonder would a supercluster inhabited by a singular hivemind count as a single creature?

By some definitions, sure, but assuming there are no methods of FTL, it would essentially function as lots of individual planet-ish size hiveminds with blurry borders. Fighting it would be no different to fighting any other Kardashev 3.2 civilization, as if you invade one system, by the time word gets around to the bulk of the hivemind you've already conquered the galaxy.
There is functionally no difference between a hivemind and any other type of empire at the interstellar scale, as when it takes years for messages to go from A to B, the few hours you save by sending them directly along synapses instead of having individuals operate in relays, are completely redundant.
Even with FTL, unless it was of Hyperion instant permanent portals type, a hivemind would have to function more as a direct democracy than a psychic mass.
Which, coincidentally, is how real-world hiveminds like ants and bees work. They don't have a psychic link together, they just operate really efficiently together.
So if we consider and ant colony as having a hivemind at that scale, humans as-is would operate as a hivemind if they were unified into any sort of interstellar empire.
So, in conclusion, maybe.

A negative 3.

An exterminatus is enough to wipe out an entire sector. But this monster is what, 1 billion times that size? Not even the imperium in 40k could kill it.

Exterminatus should reasonably be available to a K2 civilization, and the entire power output of a single galaxy (K3+) should be enough to kill something that's like 10-100 galaxies big, so it's where exactly between 2 and 3 you need to be.

see anons and Life doesn't means a blob of meat

Reminder.

According to our current understanding of physics if we were able to go FTL the exit point would destroy an entire solar system by ricochet, just scale that up.

(1/7)
There's lots of different ways such a thing could exist. Personally, I think that a supercluster of galaxies populated purely by discrete intelligences (though what we call “intelligence” might not be present in anything but the overall collective being, it’s perfectly possible that sentience only develops out of the gestalt of the collective whole, or perhaps not even then), with K3 in each and every galaxy, operating under goals decided by the collective over unimaginable timelines, to be something like a "space monster", in that it's monstrous in scope, and presumable regard towards lesser beings not a part of its mass. Whether or not it's alive is debatable, however I believe that (in a sense) it fulfills all of the eight generally accepted criteria for something to be "alive":
>Movement
It's perfectly possible (over the stupidly huge time-frames upon which this organism operates), to move entire galaxies, and, yes, in theory super-clusters, using something called a Shkadov thruster: a mega-structure that uses a stars radiative output to generate thrust. It's true that not everything in an entire galaxy, or supercluster, is a star, but, if you're moving that much matter, gravitational attraction is going to drag the surroundings along with it.

(2/7)
>Respiration
I'd assume that the fusion within the stars is what counts as respiration in such a "being", as it would function in much the same way as respiration in more mundane organisms: a fuel source, which is converted into a format more easily usable to the machinery in the rest of the creature.
>Sensitivity
It would be implausible to suggest that this being were entirely insensate to its surroundings, in fact, it would be highly likely to use outside information to aim itself towards other galaxies/superclusters, or steer itself away from other superclusters/galaxies or other such regions that show signs of other life such as itself. I am assuming in this case that internal monitoring doesn’t count as Sensitivity in this case, as it falls under a different category in classifying life.
>Homeostasis
I find it likely that a being such as this would manage gas clouds, star forming clusters, general nebulae, and rogue black holes, to give a few examples from a long list, in order to most efficiently make use of the resources within itself, such as by toggling the compositions of new star formations to fiddle with certain statistics about them such as final elemental formation, violence of their death, luminosity, lifespan, and so on, or mopping up rogue black holes that could swallow up otherwise useful fusion fuel for a long timespan. This list of possible maintenance tasks are endless, and I’m sure that many would be on frankly titanic, inhuman scales.

(3/7)
>Growth
I’ve already mentioned that such a being might use senses to find promising areas to reach towards, in order to reach and engulf, then prepare all mass that it encounters. It’s hard to imagine anything like this not growing, in fact.
>Reproduce
The only reason this creature would take so long to get anywhere is due to the fact that it’s got to move all of its mass, not just the engines which are doing the travelling. Sending relativistic probes out everywhere (most likely in, as seems to be a pattern with this beast, unimaginable numbers), would get to other places far, far away from this being in what, to it, is at best an eye-blink. Personally, I think that these beings, if they split, would do so simply because it’s faster to assimilate matter that way: why just become one galaxy at a set rate, when you can become that galaxy at the same rate, but also several thousand others simultaneously at the same rate (minus a small time at the start to colonize and send more units to the rest of that thing)? The answer is, of course you’d send “separate” beings ahead in order to spread themselves faster, as long as you can essentially just become one again by occupying the same (or, a near) space.

(4/7)
>Excretion
This one’s a little harder to explain, though I think I have an answer here too. In all galaxies, there’s such a thing as the interstellar medium (which not only existed before this was a part of the organism, but would be created by components of the organisms basic respiration, and also industry, accidental destruction of almost invisible space rock in the way of your beams of whateverthecrap, and so on). This is gas, dust, et cetera, that exists between stars, and serves, in a being such as this, purely to vastly slow down physical transport, and more importantly, diffuse ion beams transporting matter, and laser beams transporting information. Getting rid of these (read: hoovering them up using something gravitationally attractive), is going to greatly improve the performance and efficiency of the entire small scale mechanics of the organism (pfft, “small scale”).
>Nutrition
Not only would this organism need hydrogen (or something else, though it would probably be hydrogen) for their metabolism, but they’d need all sorts of other elements to do fancy things, like make those huge mirrors for the Shkadov thrusters, for example. Luckily for our organism, all of those lovely heavy elements come in the same nice convenient galactic packaging as the hydrogen.

(5/7)
Of course, it’s implied that this being is at least fairly intelligent, in some sense at least, so, what’s its goal? It’s goal could be all sorts of things, from being an ancient AI who was last told to just expand, to an intelligent, sentient being, whose aim is to collect more matter than would otherwise be conserved in whatever its home area was from purely gravitational attraction, in order to last orders of magnitude longer at the end of time. Oh, and as for weak spots? On such huge scales, anything with even a modicum of sense would be entirely distributed and decentralized: you’ve cut the head off the snake? Well, now you just have a huge galaxy-eater on either side of you.

(6/7)
A quick note of warning though: the being I’ve described overall would most likely work much more efficiently than this, calculating which galaxies are salvageable, sending probes out to them, converting them, and then bringing them back to some planned central hub area. Also, (if we’re regarding one of the galaxies/local groups defined as travelling towards the origin point under its own power, ie the Shkadov thrusters being used in one direction mainly), these individuals would probably attempt to close their geographical area to as dense one as possible, in order to maximise gravitational attraction between the super structure, to minimize the loss of extraneous pieces of valuable matter. Now, if we’re not regarding one of the super-clusters moving under its own power, then their goal would probably be to shut down as many stars or other radiating objects as quickly as possible, and to enclose anything they couldn’t stop emitting: any mass, even the almost meaningless amount within light, is valuable. This would probably involve stuffing as much stuff as possible into black holes (very carefully, if it goes wrong, you’ve lost more stuff than just leaving alone, an accretion disc is a disaster), and just coasting your now ex-supercluster towards the central repository of matter, be that an individual, stupid huge black hole, or smaller ones in order to not bar all of the eventual hawking radiation until its too late.

(7/7)
I’ll be perfectly honest OP, this is a question that’s a lot more interesting than it appears at first glance, I’m glad I opened this thread. Of course, I haven’t answered your question really, and that’s because I only have, at best, a sidestep: if you’re not also a maximally efficient collective with K3 domination over multiple galaxies within proximity of it, GTFO OF THE FEASIBLE RANGE WITHIN WHICH IS CAN BRING ANY AMOUNT OF MATTER BACK TO ITS HUB AT A PROFIT. You can regard this zone as an exclusion zone, as anything entering it will probably not be respected. If you’re outside of this zone, you might be spared simply from indifference to your insignificance, though, it seems more likely to me that you would be exterminated from the face of the observable universe purely due to some automated cost-benefit analysis to calculate whether or not the permanent energy expenditure of destroying you would be worth it to stamp out the vague chance that your could do some damage some day: it probably has to deal with such a situation every couple million years, given how much space its matter harvesting zone borders and contains. So, it sure is swell for us, that the universe is so big, and so good at hiding things: if it doesn’t know we’re there, and we aren’t profitable as mass-energy with which to collect for use aeons in the future, then we should be safe. Maybe. Lets just hope that it really IS blind to things outside of its sphere or influence, and that we aren’t within that sphere.
TL;DR: If this space monster exists in the fashion I imagined it might (there’s probably a ton of possible ways one of your scale could exist), K3 would be as good as dust before this creature, so you might want to think twice before trying to stand up to it, let alone notify your presence to it.

>K3 Civilization.
>Not don't just dismantle their whole galaxy into a more efficient and compact form into a megastructure with all the galactic mass conveniently stored and your supermassive black hole at its core.
>Not proceeding to cannibalize all the nearby galaxies too.
>Not turning your K3 into a spaceship.

Are you even K3?

Th-that was in post six user...
Seriously though, I have a weird thing for writing up ideas I have. Shame I can't put it to any good use though.

I think you might like this picture, it's a megastructure that is in its beginning of converting it's entire galaxy.

What the fuck is this bullshit? The user wants to help out the OP and asks for clarification. Were you guys that bullied growing up?

The civilization is developing into the brain of this organism, and it’s infrastructure is subsuming its biological/cosmological processes. It’s myriad Dyson swarms and Shkadov thruster nacelles are fundamentally reordering the creature.

It’s an unfriendly Boltzmann brain

just realized i'm retarded, i tagged the wrong person, it was supposed for I'm sorry user. Also how would we mount something like that? a giant kepler-novah distortion field around a supercluster? maybe made to be like a sphere of gravitational sinks that keep the monster outer galaxies into check.

>Shkadov thruster
>not a class c stellar engine

>Muh compromise
You're never going to get anywhere unless you accelerate at a whopping 0.0000000000000001c with a shkadov thruster, user, jeez!

lurk moar faggot

>very carefully, if it goes wrong, you’ve lost more stuff than just leaving alone, an accretion disc is a disaster
I love how user actually knows how mass-energy conversion works

Something of that scale would have no brain, its more like a ameba, and every single conception of one pretty much goes as user described

And yes, that is life just like we are, we're made out a unthinkable ammount of motor proteins carrying stuff around, which, somehow makes us a thinking creature out of pure conglutination of a absurd number of simpler parts without much micro connection btween itself, and, while we do have other minor parts which might be called simple intelligent beings by themselves while they do their singular tasks, we as a whole got a 'superior' macro perception of the world, so, a being like said user described, even if its one formed by literal organic life instead of mechanical "micro" workings and pieces(i dunno, drones to a megacluster of AI's and what not) it would still be a sentient creature by itself, taking decisions on a macro scale, being able to respond and react, and maybe, based on how far system and gas/dust clouds position manipulation goes it could even have a literall cluster sized brain with inner workings meddling over logic and problems far beyond what we can imagine over a scale measured in eons.

1) Google is your friend, you could have easily looked up any of those terms

2) It was obvious from the presence of "supercluster" (defined in OP's image) and "civilization" on that list that you were not sincerely asking for clarification, but were instead just being a douchetard.

So yeah, fuck off.