Melee Organelles


A continuation of this thread from the old forums:

The consensus on that thread (correct me if I’m wrong) was to not include a “spike” organelle. However, it was agreed to include a “syringe” organelle, called the predatory pilus, or just pilus, which is like a sharpened pump that sticks to a foreign cell and injects it with a certain agent (or possibly compound?). This would be one of three modes of attack, which are, in no particular order:

  1. Engulfment, where you ingest a cell smaller than yourself and then digest its contents.
  2. Agent Clouds, where you secrete certain agents as clouds near a foreign cell, and hope that it is absorbed by the cell.
  3. Pilus, where you directly stick to a foreign cell and inject it with agents.

For some basic chronology of these modes of attack, in the beginning, cells will not be able to directly attack other cells at all. Then, some species will evolve engulfment edges, which will allow them to absorb other cells. After a while of cells absorbing each other, agents will be introduced to the scene, and some cells will adapt to use this mode of attack. Again after a while of this, pilli will be evolved, and now some cells will adapt to use this to hunt other cells.

What are your thoughts on this concept? What can be improved or should we keep it the same? If we can straighten it out soon, we might be able to get pilli in for the next release.


I like it. (Sorry for typing so little, but this is exactly what I was thinking, so I don’t have anything to add.) Also, this is a bit off topic, but guess what the first thing that pops up when you google image search for “predatory pilus”? It’s Thrive!


I want to make two points.

1- I am against this general idea of the microbe stage having a linear progression. You start out weaponless and then develop weapons in the above order while upgrading your organelles. I think this will mean there is basically 1 playthrough of the stage and once people have done that then they are done and waiting for the next stage. I think we want to be looking at simulator games for inspiration. IMO you should play once (as say a big photosynthesizer) and look at the small fast cells and think, “that looks really fun.” So you start again and play as a small fast cell and see other cells using agents and think that looks cool so you start again and play as an agent producer. I think the best thing to be should be whatever everyone else isn’t doing. If everyone else is giant cells with all these crazy features the best thing to be should be a small cell with 1 flagella, you can just go round hoovering up resources while outpacing these big cells. IMO the game needs to be paper-scissors-stone and not a race along a tech-tree, because basically you can only do that once. For this reason I think every upgrade needs a drawback.

Now this is just a suggestion, I don’t care if we make this or not, it’s just an idea. What do you think? Does it sound fun? Remember the goal of the project is to make the most scientifically accurate thing we can which is fun. Fun comes first.

2- What I have been suggesting for this is to have 3 “archetypes” and push the advantages and costs of different improvements in such a way that you are forced to choose between them (of course you can be anything you like but IMO a cell that has everything should be super weak). So the 3 archetypes would be

a. A large cell with lots of melee damage pilli on it. It can command an area of resources and is much stronger than

b. a small fast cell (imagine a sperm) with a single pilus. It can run from the large cells but can’t defeat them. It can, however, run down and catch

c. agent producers who are medium speed but are able to produce a lot of different agents. They are unable to escape from a small, fast cell but can take time to destroy a large, immobile cell.

so a. beats b. beats c. beats a. The gameplay then becomes about range control (who is faster) and how much hp and damage you have (hp can either be raw hitpoints or, much better IMO, a model of how well your cell is functioning with osmosis pumps etc). If you choose to put everything on your cell then you become big and slow and you burn so much protein making agents it’s really hard to grow / reproduce so you become rubbish. I think this is a good system because it goes on forever. You need to adapt to whatever niche is available. If everyone else is big and slow get agents. If everyone else has agents then become small and fast etc.

Now this is just an idea. I am totally happy for this not to be made or for us to be make anything else. However I do think it is a mistake to go with a linear, upgrade based, pathway. It might be more realistic (in terms of microbes developing) but we need to think about re playability and fun (because this has to last for years before the next stage is finished).


Could a possible benefit of melee agent transfer be not having to worry about accidentally killing your own cell with an agent cloud? I’m unsure if that risk is currently in the mechanics or not, but I could see how it might be a bit imbalanced to be able to flood an area with deadly agents and then just sit right in the middle of it with no possible repercussions to yourself.


I believe the last place we got to with agents was this.

Each agent has a code, each organelle has a code. if the agent comes into contact with the organelle AND the codes are sufficiently close then the agent shuts down / slows down that organelles function for some time (possibly proportional to the closeness of the codes).

So if my agent has code 1111,1111 and your flagellum has code 1111,1110 then if it touches the agent it will get pretty heavily shut down. But if your mitochondria has code 0000,0011 then it won’t get affected by the agent.

If we are going with injecting agents with pili then if you spray agents into the water then they should only affect the organelles on the outside of your cell (and maybe there could be a slow rate of absorption) otherwise their is no advantage to injecting. Then if you inject you affect all the interior organelles.

So with your own agents you would need to be sure anything you spray has a very different code from that of your exterior organelles.

However this is only where the discussion ended up. What get’s built could be very different.


Out of curiosity, how many agents are we dealing with in any instance? Does a cloud consist of a few dozen or a few thousand agents?


Right now I think compounds are discrete, you pick up those lego looking blocks. I think the idea has been to move to compound clouds, so that represents them more as a density field. I think that’s the idea anyway. That would represent millions of tiny proteins I guess.


I mostly agree with what you said. I think I wasn’t very clear with my example. When engulfment starts to evolve among the species, they won’t all evolve it. The photosynthesizers will already have a pretty stable position, as would the thermosynthesizers (if LAWK was disabled). There would simply be a strong selective pressure for the cells to diversify their diets.

Same with the appearance of agent use. Engulfment edges aren’t a prerequisite to agent vacuoles, it’s just that evolving agents is a bit more complex, so it’s much more likely for engulfment to appear among species first. And when agents do appear, selection should only favour some of the species to adapt to using that, while others will remain with engulfment or swimming around absorbing nutrients, or sitting in light/heat. It’s very possible for a cell to evolve straight from being a swimming-around-eater to using agents.

With pilli, there’s a bit more dependence on earlier mutations, because you can’t inject them with agents if you haven’t evolved agents yet. However a pilli is still not universally better than agent secretion. To be able to catch and stick to a cell to inject it, you would probably have to be quite fast, and resistant to a lot of agents you might have to swim through. You also wouldn’t need to produce as many agents, since you are injecting them all directly into a cell. This means that cells that primarily use agent secretion would probably be big cells with large vacuoles to release large amount of agents into the environment, to maximize the chance of it killing another cell, while those that use pilli would be smaller, faster, and more agent resistant, except with less agent production since they inject it right into their target. It’s also possible for cells to evolve agents for an auxiliary purpose, such as hindering predators, and not as a primary mode of attack.

I’m not too convinced on the idea of creating archetypes. I more support the idea of creating natural drawbacks to trying to specialize in many things at once, and letting roles develop dynamically. For example, every hex of cytoplasm or organelle you add decreases your speed, increases your ATP cost, and decreases the rate of transport of compounds into and out of your cell. These three are major drawbacks, but for some cells are outweight by the benefits of the added organelles. However past a certain point even more of these organelles would not be worth the penalty to speed, ATP, and transport rate. Therefore you’re working with a pretty limited size, so you will have to tactically choose which organelles you want to fill that space with.


So what is the mechanism that unlocks these new things then? Is it just time or is are they all available from the start. How do new things become unlocked?

I get what you are saying. One approach is just to build something, anything, and test it to see if it’s fun. Whatever we build first draft will almost certainly not be fun, that’s the nature of game design. From there we will get clues as towards what might work.


Agents should statistically appear later than engulfment, because engulfment is just a single adaptation, with later adaptations just increasing the surface of your membrane that can engulf. However, in the current concept agents first evolve as agent secretors, which you can place whenever you want. When you place an agent secretor, it will be assigned an agent with a random effect that is quite minor. Your cell will start to produce that agent, but it will immediately be secreted by that agent secretor, until you evolve an agent vacuole, which you must assign to that secretor, and then the agents will be held in storage first and secreted on command. You can also evolve the agent to change or magnify its effect. All of this should take several generations longer than the step to engulfment.

Now that I think about it, I feel like the current concept on agents is a bit counterintuitive. You first evolve an agent secretor but you have no choice but to constantly secrete them? If anyone else would like to discuss this I think it would be worth it’s own thread.


You don’t have to constantly secrete them. You just hold a key to keep releasing one, and release it (the key) to stop.


Sorry I don’t understand. What mechanism controls this late appearance?

Specifically I am playing thrive, I play a bit and get some mutation points. I want to put an engulfing edge on my microbe. Can I do this immediately? Is it on the list in the editor? Is it greyed out until a certain amount of time has passed? Does it randomly appear to one species and not others? What I’m interested in is the mechanism for how this will be enforced on the player.


Engulfment will cost a certain amount of MP for each membrane hex you place it on, but costwise you will be able to adapt it in one generation. After this one generation of evolution you will have a fully functioning ability to engulf other cells. The ability to place engulfment edges is present from the very beginning.

To develop an agent system for predation, you need three different steps. First you need to place an agent secretor. Then you need to place an agent vacuole. Then you need to upgrade your agent so that it’s effective enough to use as a primary mode of predation. The secretor is unlocked from the beginning of the game. The vacuole requires a secretor.

These three steps will not be possible in one generation, probably three or four, so by the time some species have evolved a fully developed agent system, chances are very high that there have already been several generations of engulfers evolving. There is no hard coded mechanism that stops agents from appearing before engulfment. It just takes more steps to evolve it, since it costs more than 100 MP to do all those mutations.


1- So you’re saying that if it’s my 50th playthrough, and I want to play as an agent secretor, I have to do 3-4 generations of swimming around as a herbivore before I can start playing? That sounds kind of lame. What if I want to be a predator and not a herbivore? I think if you’ve done the first mutation you’ve already said “I want agents” but now we’re going to force them to go back out and play 2-3 more generations of just collecting tokens before they can get what they want? That doesn’t sound like great gameplay, sounds like grind to me (“you haven’t got enough coins to unlock this, go and gather more, you need to fill 3 pots and your pockets only carry 1 pots worth”).

2- I’d like the biologists to weight in here as I don’t know if I’m right about this (summon @Seregon ) but I thought the whole point was that each successive mutation has to confer benefit. So an eye starts as some light sensitive cells (and just that is useful) and then starts to fold into a well (and that is better) and then gets glazed over and becomes an eye (which is even better). If light sensitive cells had no advantage then there would be no reason for them to spread.

So with this agents system the problem is that the first couple of steps don’t really have an advantage attached to them so why would they spread? It’s not realistic that you would evolve your whole population to have a useless agent secretor because “it will be useful in the future, you guys stick with me, serious this will be really good.” So maybe I’ve misunderstood what your saying and maybe each stage will confer a partial benefit.

Moreover there’s another problem that auto-evo picks the best mutation for this generation so if multiple steps are required you’re going to need to redesign how the auto-evo works to make it pick things which are at first useless but later confer benefits.

So it sounds to me, IMO, that what you’re suggesting won’t be fun or realistic. But that’s just me.

3- On a larger level I don’t think we are going to discuss until we agree, I think we are drifting further apart. So I’m going to step back, I’ve said what I think above. I would much rather see something built than the thing that I want. If I can help let me know how and if you want to know what I think feel free to ask.


If you’re interested I’d be glad to talk to you about it via PM (maybe on Slack if it’s easier), because a lot of what you asked is things I hadn’t considered before and it’s a good test to put the concept through to see if it warrants changing.


I wasn’t involved in the decision to create an agent secretor, so I don’t know what the idea behind it was, but I’ll throw in my two cents:

I would think that before you can evolve a specialized part of your cell to secrete agents, you’d first evolve the mechanism of secretion, which would happen all over your surface until you see fit to evolve, say, a polarization mechanism to make the secretory vesicles congregate at one region. The only way for secretion to arise in a localized part of your membrane is for it to evolve by co-opting an already-localized mechanism to make it secrete stuff. For example:

Let’s say your cells are sessile and form monolayer colonies. Each cell is polarized with an apical side and a basal side. You perform pinocytosis on your apical side, so you have vesicles constantly budding off, fusing with endosomes to release their captured solutes, then returning to that membrane. Then, through some fluke of evolution, a digestive enzyme which was previously sent to the late endosomes (in preparation for fusion with a lysosome) instead starts getting sent to the early endosomes, and thus gets carried out of the cell by pinocytic vesicles returning to the apical membrane. Thus, by co-opting an already localized process, you secrete something locally instead of globally.

But I think such an example would be too complicated for us to easily model in this game, so I’ll finish with a simple point: I think that, instead of creating a localized structure immediately and then specializing it to secrete agents at certain times or whatever, we should reverse the order – first evolve secretory vesicles to secrete agents all over your surface, then evolve mechanisms to regulate location, timing, type of agent, etc.

Pilus, Defenses Against pilus, and pilus variations

Choosing between a general leak, which lets agent out all around you, and a spray which puffs it in one direction but takes time to recharge, would be a cool choice.