Home bug spray

[TheSaddestGoomba]

Summary

Content "Add household pesticide spray cans"

Purpose of change

Spray cans of pesticide are a common household item but are currently absent in game.

Describe the solution

Create a 'spray can of pesticide' item. Place it in the world.
It is based on the existing 'spray can' item that here is renamed to 'spray paint can'
Using it runs an EOC that prompts the player for an adjacent tile and places a field there. The field used is the existing "insecticidal mist" that is already used by the chemical thrower and insecticide gas grenades. The HP reducing effect is hardcode tied to that field_id. The same EOC removes the field after a 1 second delay

The field_id is edited to apply "insecticide in eyes", "insecticide in mouth", and "poison" effects, all taking env_resistance into account.

Seed the item into appropriate item_groups and mapgen.

Describe alternatives you've considered

Adjusting the ammo count, effectiveness, etc.

Testing

The item spawns in debug no problem.
'use' action EOC functions and spawns the desired field, and clears the field a second later.
Ammo count and duration of the gas field both feel comparable to IRL.

Combat tests feel appropriate:

• 'oversized wasp' can be killed with the item (2-3 sprays).
• 'oversized cockroaches' likewise take 2-3 sprays.
• 'giant dragon flies' and 'oversized mantises' barely survived a whole can.
• 'giant wasp' may lose from 1/2 to 2/3's HP from an entire can and will probably kill you before you even could.
• 'oversized ant' 1 or 2 sprays depending on exposure.
• 'giant ant' was similar to the 'giant wasp' but more consistent due to lower mobility.
• 'super soldier ant'... lol, no. You might as well be spritzing it with water. A full can barely left a mark.

I'm pleased with the state of the item. The above examples hold true for using the item "effectively".
It could be a life-saver early on against the weakest oversized bugs but falls off quickly as the targets get larger. It is also suitably difficult to use properly in a fight. More mobile creatures will take less damage, and ones that flee will be impossible to keep in the gas to finish them off.

Tested item spawn by upping the probability and porting around the map through debug.
Spawning is functioning, although rarer than I would like with the final probabilities. I'm going to leave the numbers as they are for this PR, as I expect they are more frequent than my testing indicates due to hidden items in furniture and containers.

Additional context

Item placements include hardware stores, home garages, janitor's closets, farm chemicals, and trash

[Maddremor]

Why would a household bug spray have an effect on animals that are 10kg at minimum?

[Milopetilo]

You might also want to add these to SUS_kitchen_sink so houses have bug spray.

[TheSaddestGoomba]

These sprays are more than the simple soapy water method that suffocates insects by blocking their spiracles. It's a combination of neurotoxin and boric acid, typically. Wasp and hornet formulas usually add a paralytic as well but I'm keeping this simple and more generic.

The monsters that it affects most strongly are still small enough to completely saturate with a neurotoxin designed for them. The larger creatures are already much more resilient due to their HP.

[ADekema]

I think that household bugspray is a good adition to the game to be a source of chemicals and insecticide. I doubt that spraying a insect the size of a small dog or cat is going to do much. Most likely you would either have to motify the thing into a weak gas grenade that releases all the spay at once so the insect gets a good wif of it, or you would need to spray it on an arrow and shot the arrow into the insect so that the toxin get´s into it´s blood.

[Rabadash94]

Even if the bug spray isn't fatal due to the weight of the bugs, it should still serve as a repellent and keep them away for some time. Perhaps a few tiles from the point where it's applied. This could be useful in many situations, and even for making some traps.

[kevingranade]

The lethality seems quite high to me, this stuff is at its intended "quick kill" effectiveness when you absolutely douse the target with it, dropping that dosage by an order of magnitude or more seems like it would make it wildly ineffective.

Possibly a starting point would be setting the cloud of gas it produces to disperse even faster, i.e. a half life of 1 leading to it essentially dissipating immediately. This also better reflects how these things work, they don't emit a cloud of gas that lingers for several seconds, they disperse immediately.

In that vein though, "fogger" insecticide cans also exist that ARE intended to saturate an entire room with insecticide, might be worth looking into.

[TheSaddestGoomba]

I'm reverting to draft while I work on some changes to, hopefully, make this JSON only.

The original intention was for the ”spray can of insecticide” to simply use the existing insecticidal_gas object, thereby applying all of the same effects.
That did not work out as changing field duration (afaik) requires a new field object, which requires adding that new field to the existing hardcoded effects. On top of that, the existing field represents a cloud of fumigant not a direct spray. Not a good approach.

Instead, I’m going to implement all effects through JSON. Characters will be poisoned through exposed eyes and/or mouth, plus blinding, coughing, irritation, etc.
Monsters and post-threshold mutants will take damage while in the field, at the moment I plan to base the damage numbers on the hardcoded functions.

Addressing efficacy on embiggened bugs, I certainly expect that a larger insect would require a larger dose. I feel that’s well represented here through HP alone.
Most of these sprays use pyrethroids as the active ingredient which permanently shut down neurons. The doses required are incredibly small, even relative to a tiny insect. Higher concentrations provide little benefit, so the bulk of the volume of these sprays is vehicle fluid designed to deliver the neurotoxin more quickly and effectively. They can be absorbed through the cuticle or inhaled through the spiracles that cover a large portion of insect surface area. The arthropod circulatory system (not just size) makes it a very short trip from there to the nervous tissue. It only takes a small amount of blocked neurons to disrupt motor and life functions.
Increased body size only aids resistance by increasing the distance the toxin has to travel and the number of neurons there are to be blocked. That last aspect is also limited by the tissue structure, as you don’t need to block every neuron, just enough in the chain to disrupt signaling.
Generally speaking, neurotoxins take microscopic doses to kill even large animals; they really only need macroscopic assistance in delivery. As an example, VX nerve agent has a lethal dose of less than 700 micrograms for a 200lb human.

@kevingranade
I believe the insecticide gas grenades are meant to represent foggers. That was always my impression at least.

Is it the total sum of damage you feel is too high? Would stretching the same amount out over a few seconds change anything? I could create an effect to represent a target being coated in it and absorbing the poison more slowly.
Agreed on the dispersion for the spray can. There’s some variance between patterns, usually a wide cone or a long stream but little short-lived mist. I’ll cut the duration down to a minimum. Half life 1 was too short to trigger its effect through monmove, I’ll see if attaching the effects to the field in JSON can avoid that.
A better implementation that accounts for surface coverage would likely be possible after #72271

[kevingranade]

Is it the total sum of damage you feel is too high?

Yes, it's total damage, it taking a dozen seconds instead of a few still seems off. If you do cut the duration of the field and leave the rest unchanged that should lower it plenty, if you chased a dog sized insect around spraying it constantly yes I'd expect it to have significant impact, it's just it getting re-dosed over and over again via the field lingering that I think ratchets things up too far.

If you want to be convincing about your "it's a neurotoxin so size doesn't matter" argument get me a reference that agrees with you, because it contradicts what I understand about toxins in general.

[TheSaddestGoomba]

Yes, it's total damage, it taking a dozen seconds instead of a few still seems off. If you do cut the duration of the field and leave the rest unchanged that should lower it plenty, if you chased a dog sized insect around spraying it constantly yes I'd expect it to have significant impact, it's just it getting re-dosed over and over again via the field lingering that I think ratchets things up too far.

If you want to be convincing about your "it's a neurotoxin so size doesn't matter" argument get me a reference that agrees with you, because it contradicts what I understand about toxins in general.

Roger that on the damage. The newest version uses an EOC to remove the field 1 second after creating it which will limit the damage rate.

My argument was never that "size doesn't matter because it's a neurotoxin." I stated in the same comment that I expect a larger creature would be more resistant due to body mass (higher cell count), represented in-game with their higher HP.
My point was that size scaling can be tricky with regard to toxicity, with application method and the core mechanisms often having more impact on lethality than size.
Here's an NIH article that covers the mechanism of action for pyrethroids:
https://pmc.ncbi.nlm.nih.gov/articles/PMC10707950/
Another that examines the entry method (apparently cutaneous absorption is milder, inhaled is most effective):
https://pmc.ncbi.nlm.nih.gov/articles/PMC5073107/

[Maddremor]

In practical terms, how does this compare to using a stick in terms of weaponry? Given it's a spray can you aren't getting extra range out of it, and the size of the target is 1000 times the mass at minimum. If it wouldn't work, I don't see the need for inclusion as a weapon as opposed to a chemical component.

[TheSaddestGoomba]

In practical terms, how does this compare to using a stick in terms of weaponry? Given it's a spray can you aren't getting extra range out of it, and the size of the target is 1000 times the mass at minimum. If it wouldn't work, I don't see the need for inclusion as a weapon as opposed to a chemical component.

I'll start looking at how to make it 'harvestable' for the chemical component.

I don't think its comparable fitness as a weapon is really at issue. It's not intended to be weaponry per se, not any more than in real life. It should do in game what it does in real life. The real question is how should it affect the things that don't exist IRL?

I'm still searching articles for information on lethal doses for insects and the effect of size on those doses. 1000 times the body mass doesn't necessarily equate to a 1000 times increase in volume for a lethal dose. Also consider that these household sprays don't have concentrations right at a lethal dose for natural insects. They're designed for overkill to ensure an effective product.

As an example, this Raid product (https://a.co/d/1xsCGB5) has an approximate pyrethroid content of 70.2 grams, or 70,200,000 micrograms.
This fact sheet states 'as little as 0.02 micrograms [of pyrethrin] sufficient to kill a bee'. 1000 times the lethal dose given is then 20 micrograms.
https://web.archive.org/web/20150319214346/http://www.xerces.org/wp-content/uploads/2009/12/xerces-organic-approved-pesticides-factsheet.pdf

[Maddremor]

What is the LD50 for an insect, and what is the LD50 for a human? I have a suspicion that we shouldn't have insecticide as a weapon in the game at all, just poison gas that works roughly the same for everyone living.

[TheSaddestGoomba]

I've not found much clear information on the LD50 for various insects but I do know that it does vary quite a lot with species.

The LD50 for a human isn't going to tell us anything about effects on an arthropod. Pyrethroids are used because of their significantly lower toxicity to mammals. That's not just a size thing, it's anatomical differences at the macro and micro scales.

It absolutely should not have the same effect on every living thing. That is not how these chemicals work and not a good representation of the real item.

I'm not really sure why you're referring to it as a weapon or what bearing that has?