Swarm of insects (spiders) -- How do you run this monster?

Prakriti

Hi, I'm a Mindflayer, but don't let that worry you
I'm about to run Ghosts of Saltmarsh, which includes a few encounters with insect swarms (spiders). As I read the stat block, it occurs to me that I have no idea how to run this monster. Unlike a swarm of flying insects, the spiders need to crawl onto a target to attack it (I assume, because that's the only thing that makes sense). But I'm not sure how to describe this action without giving the players the impression that they're being engulfed in spiders and can't attack for fear of hurting themselves or their companions. (How the hell do you stab a spider when it's crawling on someone, anyway?)

I guess I need to make it clear to the players that the "swarm" is a monster that can be attacked, and not some sort of trap/hazard that must be dealt with creatively. But how do I do that?

(Also, the swarm has 22 HP and resistance to bludgeoning, piercing, and slashing damage, which is effectively 44 HP. That's nuts for its 1/2 CR, isn't it?)
 

iserith

Magic Wordsmith
Maybe don't say anything about it other than describing it faithfully (and disgustingly) and let them deal with it however they want. Have creative attempts to deal with that fall short of totally dispersing the swarm (e.g. throw a bucket of water, blast of wind, etc.) do some measure of damage to its hit points, just as a way to track progress.
 

Oofta

Title? I don't need no stinkin' title.
I simply describe the spiders as crawling all over the individual and get as detailed as I think my party will enjoy. I also describe the spiders as small fist-sized tarantula like spiders big enough to be hit, even if a single attack hits multiple.

Attacks are described as scraping the spiders off or slapping at them with the flat of a blade and so on. It's not perfect and "killing" the swarm just means killing enough that it's no longer a threat.
 

jasper

Rotten DM
I'm about to run Ghosts of Saltmarsh, which includes a few encounters with insect swarms (spiders). As I read the stat block, it occurs to me that I have no idea how to run this monster. Unlike a swarm of flying insects, the spiders need to crawl onto a target to attack it (I assume, because that's the only thing that makes sense). But I'm not sure how to describe this action without giving the players the impression that they're being engulfed in spiders and can't attack for fear of hurting themselves or their companions. (How the hell do you stab a spider when it's crawling on someone, anyway?)

I guess I need to make it clear to the players that the "swarm" is a monster that can be attacked, and not some sort of trap/hazard that must be dealt with creatively. But how do I do that?

(Also, the swarm has 22 HP and resistance to bludgeoning, piercing, and slashing damage, which is effectively 44 HP. That's nuts for its 1/2 CR, isn't it?)
I use the flat of my sword to kill those spiders on Jasper. I use the edge to.... SPIDERS ! AGGGH RUN AWAY GOODBYE JASPER!
Yes make it clear that a swarm can occupy the same space as Jasper. And you don't damage Jasper when you hit the swarm.
 

tommybahama

Explorer
My DM just said "a swarm of spiders crawls out of the fireplace" and put two checker pieces down on the battle map with a crude spider drawn on each. There was no need to get more descriptive. I guess you could say more to up the creepiness factor. Like when they attack, "the spiders crawls up your legs in an attempt to swarm over you" and then roll to hit.

When someone hit them with a weapon he would say "you strike at the swarm of spiders but most just scurry around the blade." I took it as meaning they had a lot of hit points. I never caught on that they had resistance to the damage. So I suggest that you make it expicit that weapon attacks don't seem effective.
 

TheCosmicKid

Adventurer
Also, when presenting swarms of insects or spiders, always ALWAYS leave open the possibility in your description that a bug crawled into one of the PC's ears and is now laying eggs in his or her brain.
Related: my PCs were on a ship that was attacked by pirates who threw baskets of giant centipedes aboard as a terror tactic before coming over the sides. Giant centipedes of course do not fight to the death and flee when injured if not slain outright. So over the course of the battle four or five of them dashed off into some nook or cranny somewhere aboard the ship... and stayed there,
 

jasper

Rotten DM
Centipedies are evil but what is more evil that is nickelipedies and what is more evil that than dimeipedies and what is more evil than than quarteripedies!
 

Weiley31

Adventurer
Also, when presenting swarms of insects or spiders, always ALWAYS leave open the possibility in your description that a bug crawled into one of the PC's ears and is now laying eggs in his or her brain.
That sounds like an unfun insta kill.
 
I'm about to run Ghosts of Saltmarsh, which includes a few encounters with insect swarms (spiders). As I read the stat block, it occurs to me that I have no idea how to run this monster. Unlike a swarm of flying insects, the spiders need to crawl onto a target to attack it (I assume, because that's the only thing that makes sense). But I'm not sure how to describe this action without giving the players the impression that they're being engulfed in spiders and can't attack for fear of hurting themselves or their companions. (How the hell do you stab a spider when it's crawling on someone, anyway?)

I guess I need to make it clear to the players that the "swarm" is a monster that can be attacked, and not some sort of trap/hazard that must be dealt with creatively. But how do I do that?
The spiders will need to start climbing on the person they're attacking, but make sure to describe the players attacks as knocking the spiders off carefully, and if a 1 is rolled maybe have the character's armor/clothing nicked (no actual damage).

Also, don't forget they can climb... I had a swarm drop on a PC in the adventure, and they freaked out (both in and out of character). Something else to remember, they have an attack reach of 0, which means they only generate an attack of opportunity if you leave their space.

(Also, the swarm has 22 HP and resistance to bludgeoning, piercing, and slashing damage, which is effectively 44 HP. That's nuts for its 1/2 CR, isn't it?)
They are on the high end of the CR, but still pretty descent*. The trick is to avoid using weapon damage, and focus on spells, fire, or even acid. In one encounter, Burning Hands was used against 2 swarms to great effect (fortunately the other PCs were out of the way). Also, their damage goes way down once they're at half HP.

*You wanna see nuts for CR 1/2, check out the Shadow. This can scare characters of almost any level.
 

MNblockhead

A Title Much Cooler Than Anything on the Old Site
That sounds like an unfun insta kill.
As @BookBarbarian said, I would treat it more like a condition. After all, in the real world, spiders, wasps, and flies that lay eggs in other creatures, the larva don't kill the hosts immediately. It is a long, slow process of being eaten up from the inside. Maybe they don't even kill you, but until they dig their way out you suffer some disadvantage. Maybe they control your brain, giving you an effect like a geas spell that compells you to put yourself in a position to be eaten by a Roc, because part of their lifecyle involves developing in a Roc's gut.

Maybe the parasites inject a chemical that make the player find some place underground to hide out in, refusing to leave until slowly eaten, allowing the larva to mature in relative safety.

Of course various restoration spells, poison remedies, and medical checks may cure the character depending on the natures of the parasite.

Lots of fun things you can do with parasites:

 
I'm about to run Ghosts of Saltmarsh, which includes a few encounters with insect swarms (spiders). As I read the stat block, it occurs to me that I have no idea how to run this monster. Unlike a swarm of flying insects, the spiders need to crawl onto a target to attack it (I assume, because that's the only thing that makes sense). But I'm not sure how to describe this action without giving the players the impression that they're being engulfed in spiders and can't attack for fear of hurting themselves or their companions. (How the hell do you stab a spider when it's crawling on someone, anyway?)

I guess I need to make it clear to the players that the "swarm" is a monster that can be attacked, and not some sort of trap/hazard that must be dealt with creatively. But how do I do that?
Think of the swarm as being a central malign intelligence. Individual spiders may crawl up a PC's legs and bite them, but the mass of the swarm is still on the ground at their feet or on the wall by them. It's driving off the heart of the swarm that's important, not a few stray spiders. When the swarm moves (or the PC moves), describe how it's easy for the PC whose space was once occupied by the swarm to shake off any lingering spiders.

(Also, the swarm has 22 HP and resistance to bludgeoning, piercing, and slashing damage, which is effectively 44 HP. That's nuts for its 1/2 CR, isn't it?)
Not really. It's at the higher end, yeah, but several CR 1/2 monsters (e.g. Shadow and Jackalwere) have resistance to B/P/S damage, and if taken into account as doubling HP would place the Shadow at 32 HP and Jackalwere at 36 HP.

Proper response by a non-spellcasting character when dealing with a hostile swarm is not to draw your swords. Instead, it should be to get out the torches and lamp oil. Or burn some insect repellent. Or trigger a smushing block trap to drop on it. Or lead it into another monster in the dungeon.
 

Prakriti

Hi, I'm a Mindflayer, but don't let that worry you
Lots of good suggestions here. I like the idea of running the encounter as more of a trap/hazard and counting any PC actions directed at the spiders as a "hit."

When I made this thread, I was pretty set on swapping out the swarm for a single giant spider, but now I think I'll stick with the swarm.
 
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