Bombs, Swarms, and Allies

[Riggler]

Scenario: A Large Rat Swarm occupies a 4-quare space that contains 2 PCs. An ally of the PCs throws an Alchemist Fire bomb at the Swarm creature and hits.

How I ruled: I ruled that Alchemist Fire did full damage to the creature and everything in the four spaces the Swarm creature occupied, and did splash damage to allies and enemies adjacent to the Swarm creature.

The reasoning: The AC calculated to hit the large Swarm like any large creature is taken into account. PF2E doesn't by RAW allow targeting just a single square of a Large or bigger creature. And even if it did, in the case of a Swarm, I think doing so defeats the purpose with a Swarm's weakness to area and splash damage. Splash damage on bombs is applied to both the creature hit and adjacent creatures. But the PC allies were not "adjacent" to the target of the bomb, but occupying the same space as the target of the bomb. Previous editions from the current also clarified area attacks on a swarm occupying another creature would hurt that creature as well.

Did I rule RAW or is there not RAW for this specific scenario?

Would you have ruled the same or differently? If differently, how and why?

[shroudb]

You didn't rule RAW.

Raw is pretty straightforward: A Strike targets a creature and only damages said creature regardless how many creatures are in the same area.

There are multiple ways that multiple creatures are in the same space, that doesn't somehow turn Strikes into area effects that hit all of them.

The ONLY trait in the bomb that deals area damage is the Splash Trait. So the players should only have received that portion of the damage by RAW.

[Dr. Frank Funkelstein]

I would allow to targeting a single square of a swarm (even though there are no specific rules for it), which would not trigger the area vulnerability, but the splash vulnerability. I checked a few swarms, the values for area and splash vulnerability were the same on all of them, so it would only make a difference for other creatures in the swarm.

[Luke Styer]

Riggler wrote:

Splash damage on bombs is applied to both the creature hit and adjacent creatures. But the PC allies were not "adjacent" to the target of the bomb, but occupying the same space as the target of the bomb.

Here are the rules on Splash.

Of note to your scenario, "If an attack with a splash weapon fails, succeeds, or critically succeeds, all creatures within 5 feet of the target (including the target) take the listed splash damage."

Nothing about "adjacent" there, If the PCs were occupying the same space as the target they were necessarily "within 5 feet of the target[.]"

Quote:

Would you have ruled the same or differently? If differently, how and why?

On the "regular" damage, there's no reason the PCs should have taken that damage. Alchemist Fire doesn't deal area damage, so it only damages the creature hit.

I'm unclear what you actually did with the splash damage, so I can't say whether I'd rule the same way or not. But to be clear, the PCs in the space occupied by the swarm would take splash damage.

I don't really understand what this talk of "targeting just a single square of a large or bigger creature" is about or has to do with any of this.

[Luke Styer]

Dr. Frank Funkelstein wrote:

I would allow to targeting a single square of a swarm (even though there are no specific rules for it), which would not trigger the area vulnerability,

Alchemist's Fire doesn't deal area damage, so by default it would never "trigger the area vulnerability."

Quote:

I checked a few swarms, the values for area and splash vulnerability were the same on all of them, so it would only make a difference for other creatures in the swarm.

RAW, if you attack a creature with a splash weapon in order to trigger a weakness, you are making a choice to accept dealing splash damage to any allies "within 5 feet the target[.]" You're weighing a benefit (triggering a weakness) against a cost (splash damage to your allies).

Unless you impose some sort of penalty when you allow a PC to target "a single square" of a swarm with a splash weapon to manipulate the splash damage (which also alters how splash damage works, because it checks for proximity to the target, not proximity to a particular square), then you're making that decision a lot less interesting, because manipulating the splash damage will always be better choice if it's possible.

[Riggler]

Thanks for the clarity, you all. I'm new to PF2E and have lot of other versions of very similar game systems floating around in the noggin [All versions of D&D (except 4th), and PF1 to name a few].

[Luke Styer]

I often think I'd have been better off learning Pathfinder 2E Remastered as a complete blank slate than with Pathfinder 2E, Pathfinder 1E, and D&D 3.X, with their subtle differences already baked in.