Unclear swarm rules

[Michael Thayne]

Somehow, until recently I'd never run a fight involving swarms. Trying to do so left me with a lot of questions:

• Since swarms have no Basic Speed, where do they go in the turn sequence?
• Since swarms have no Will, do they automatically fail to resist Animal Control spells?
• When a swarm moves, who gets damaged that turn? Only people in the hex where the swarm started? Only the people in the hex where it ended? Or anyone in any hex it passes through?
• Do swarms even inflict damage on their turn, or on their victims' turn? If the latter, is it at the beginning or end of the victims' turn?
• How does running through a swarm work?
• Can a swarm "stick to" a victim that tries to run away from it? (Includes say a wizard casting levitation to escape a ground-based swarm.)

AFAICT most of these questions aren't even clear in vanilla GURPS, much less the intentionally simplified DFRPG rules. Though maybe some of them have gotten official answers in forum threads my Google-fu has failed to find?

[Polkageist]

They do have a move value, so I'd put their basic speed equal to that. Otherwise last in sequence is a good spot for a mindless swarm.

Speaking of mindless, they don't auto-fail, they're unaffected by animal control spells. Too many individuals in the swarm.

A swarm has reach 'C' and attacks everyone in its area on its turn, and auto-hits. It can move before or after that attack, or to put it another way it damages either the hex it starts in or the hex it ends in. Probably not both. Whether or not it also attacks targets in hexes it moves through may or may not be a special effect of that particular swarm, like say a swarm of fire motes or something.

Swarms inflict damage on their turn. See page 8 of DF Monsters for swarm attacks.

Swarms don't block space, so you can run through it. Depending on the swarm type this might be safe or hilariously dangerous.

Swarms aren't 'sticky' by default, so just think that if you move away from a swarm of something that kinda seems like it'd stick to you like ants or something, you've moved away from the main group that keeps the numbers at an effective level and any stragglers aren't in enough quantity to cause further harm. This may vary depending on the type of swarm. They're pretty flexible, so you can play around with them.

[Michael Thayne]

Originally Posted by Polkageist

Speaking of mindless, they don't auto-fail, they're unaffected by animal control spells. Too many individuals in the swarm.

This is contradicted by Spells, p. 17, under "(Animal) Control", which "Controls the actions of one large animal (any size) or a single swarm". Even if that bit of text wasn't there, you'd still have a similar issue with Repel (Animal), which is an area spell. Though in that case it seems more obvious that we are talking about ST 0 for insects and ST 1-2 (maybe 4 at the absolute greatest) for things like rats.

Originally Posted by Polkageist

Swarms inflict damage on their turn. See page 8 of DF Monsters for swarm attacks.

Good catch. I think I'd read that rule and forgotten about it.

Originally Posted by Polkageist

Swarms don't block space, so you can run through it. Depending on the swarm type this might be safe or hilariously dangerous.

Do the rules say they don't explicitly block space? +1 movement points per hex—analogous to a body lying on the ground—seems very plausible to me personally, though that's not explicit in the rules either. (I think overruns also cost +1 movement point per occupied hex, but the wording isn't wholly clear to me.)

[Polkageist]

Whoops! I stand corrected. :)

As far as blocking space, I'm going on the 'diffuse' trait that a swarm has which means that they're not substantial enough to actually block-block movement. You might have to eyeball that one a bit, since you could jump a swarm that's on the ground (ants), and a swarm of flies doesn't really have the mass to stop you barreling through. A swarm of rats or birds though, that might be substantial enough to slow you down by virtue of stepping on rats and having their poor ratty bodies roll around underfoot be difficult terrain.

e: Ah, there it is, pg35 of DF Exploits, swarms and such are automatically evaded when trying to move through their space. Goes both ways I'm sure, so a swarm can 'swarm' past you without slowing down.

[Michael Thayne]

Originally Posted by Polkageist

e: Ah, there it is, pg35 of DF Exploits, swarms and such are automatically evaded when trying to move through their space. Goes both ways I'm sure, so a swarm can 'swarm' past you without slowing down.

Thanks for this. Though while answering one of my questions, it stubbornly refuses to answer another: "less-than-solid monsters such as ghosts, insect swarms, and evil gas clouds evade and are evaded automatically. Many inflict harm in passing, however." Which ones inflict harm in passing? Who knows! Some do, some don't. Ugh.

[Dalin]

Originally Posted by Michael Thayne

Which ones inflict harm in passing? Who knows! Some do, some don't. Ugh.

I’d say that default swarms don’t do damage in passing. They attack on their turn. Doing damage in passing might be a special feature of particularly nasty swarms (explosive acid moths) or a GM call in the moment (you run through the scorpions barefoot…).

[sir_pudding]

Originally Posted by Michael Thayne

Thanks for this. Though while answering one of my questions, it stubbornly refuses to answer another: "less-than-solid monsters such as ghosts, insect swarms, and evil gas clouds evade and are evaded automatically. Many inflict harm in passing, however." Which ones inflict harm in passing? Who knows! Some do, some don't. Ugh.

Stuff with auras or persistent area affects, this probably mostly for ghosts and evil gas clouds, although some weird swarms probably also can do these things.