If an enemy has total concealment from invisibility, but is covered by a swarm, do they still get their 50% concealment?
My guess is that by RAW they do, but I think it makes sense that others would be able to see the spiders/rats/whatever the swarm is made of crawling over the air in an enemy-shaped mound, and would know exactly where to strike.
I'd say it depends on the swarm, and their particular swarming. If it's a flying swarm, they might not necessarily be covering the enemy. Instead they fly around in a cloud, and the cloud, as it encounters the invisible creature, might attack or fly around. A crawling swarm of spiders might climb up the enemy and cover them enough to know where they are, but not so thoroughly that they are acting as a "second skin." If it's a swarm of rats, they may attack the enemy around the ankles, etc, but not exactly reveal the complete and exact whereabouts of said creature.
So, really, in the end, I'd say it's up to the GM and their interpretation of the swarm and they're particular swarminess. Some things you could do are provide a circumstance bonus to hit the invisible enemy, or reduce the percentage of the miss chance.
As swarm's dont make attack roles, and simply autohit if they're in your square, I'd assume they ignore concealment or cover.
@Weables: Correct, I was asking more along the lines of "Does the swarm covering them and making it clear where they are remove the concealment for others?"
Looks like it's an "up to the GM" thing though.
Swarms fill more of the square than just surface of a character. It would be difficult to determine where the emptiness of the invisible body is in the swarm. Most swarms fill multiple squares, so you're probably looking through several feet of moving insects before getting to the part that has the invisible character.
Just assume the swarm is blocking your view fine details (like a body outline).
My apologies. I didn't infer the correct question from the OP.
That being said, RAW you'd be able to pinpoint the square (works as well as a bag of flour, or what have you) but they'd retain the 50% miss chance.
If my players used such a strategy, I'd probably downgrade to 20% miss chance as a reward for creative thinking, though again that's entirely a rule 0 rule of cool sort of thing.
The swarm subtype specifically says they cannot, so no. Bold is mine.
Traits: A swarm has no clear front or back and no discernible anatomy, so it is not subject to critical hits or flanking. A swarm made up of Tiny creatures takes half damage from slashing and piercing weapons. A swarm composed of Fine or Diminutive creatures is immune to all weapon damage. Reducing a swarm to 0 hit points or less causes it to break up, though damage taken until that point does not degrade its ability to attack or resist attack. Swarms are never staggered or reduced to a dying state by damage. Also, they cannot be tripped, grappled, or bull rushed, and they cannot grapple an opponent.
I think I'd rule it the same as Weables:
Flying swarm does not help to outline an invisible enemy.
Crawling swarm does help to outline an invisible enemy. I would personally downgrade it from a 50% miss chance to a 20% miss chance for partial conealment. If a DM opted to negate concealment completely, I don't think they'd be unreasonable to do so.
The question would be how the swarm met the invisible creature in the first place. Was the creature visible, then got swarmed, then went invisible? Or was the creature already invisible, and somehow unlucky enough to occupy the same space as the swarm?
My point is that I wouldn't allow a player to use a swarm to automatically locate an invisible creature, regardless of it being clever. But, once the swarm found the invisible creature, then game on.
The question would be how the swarm met the invisible creature in the first place. Was the creature visible, then got swarmed, then went invisible? Or was the creature already invisible, and somehow unlucky enough to occupy the same space as the swarm?
My thought process was that something with natural invisibility, like a Hellcat in bright light or something similar gave away its presence with an attack, and then the wizard/summoner/bard/other arcane caster threw a swarm on it to locate it.
The question would be how the swarm met the invisible creature in the first place. Was the creature visible, then got swarmed, then went invisible? Or was the creature already invisible, and somehow unlucky enough to occupy the same space as the swarm?My thought process was that something with natural invisibility, like a Hellcat in bright light or something similar gave away its presence with an attack, and then the wizard/summoner/bard/other arcane caster threw a swarm on it to locate it.
If, by "giving away it's presence," you mean that the wiz/sum/bard/other knows what square the creature was in, then I'd totally allow that, and high-five the player for cleverness.