I have an issue with swarms

robus · Apr 30, 2019

I find swarms to be generally underpowered in their attacks. Here, for example, is the stat block for a swarm of bats:

Swarm Of Bats
Medium swarm of tiny beasts, unaligned
Armor Class 12
Hit Points 22 (5d8)
Speed 0 ft., fly 30 ft.

STR: 5 (-3) DEX: 15 (+2) CON: 10 (+0)
INT: 2 (-4) WIS: 12 (+1) CHA: 4 (-3)

Damage Resistance Bludgeoning, Piercing, Slashing

Condition Immunities Charmed, Frightened, Grappled, Paralyzed, Petrified, Prone, Restrained, Stunned
Senses Blindsight 60 Ft., passive Perception 11
Challenge 1/4 (50 XP)

Echolocation. The swarm can't use its blindsight while deafened.
Keen Hearing. The swarm has advantage on Wisdom (Perception) checks that rely on hearing.
Swarm. The swarm can occupy another creature's space and vice versa, and the swarm can move through any opening large enough for a Tiny bat. The swarm can't regain hit points or gain temporary hit points.

Actions
Bites (swarm has more than half HP). Melee Weapon Attack: +4 to hit, reach 0 ft., one creature in the swarm's space. Hit: (2d4) piercing damage.
Bites (swarm has half HP or less). Melee Weapon Attack: +4 to hit, reach 0 ft., one creature in the swarm's space. Hit: (1d4) piercing damage.

It seems to me that a swarm should at least have something akin to pack tactics, i.e. advantage on their attacks (because of the sheer number, the odds must be ever in their favor?!) and I would even hazard that they should have multi-attack (at least while above 50% HP).

So I would add this additional trait:

Overwhelming. Due to their sheer number swarms have advantage on their attacks.

And I would modify their actions thusly:

Multiattack. While swarm has more than half HP it makes two Bites attacks.

Bites. Melee Weapon Attack: +4 to hit, reach 0 ft., one creature in the swarm's space. Hit: (1d4) piercing damage.

Thoughts? And does anyone else have ideas for enhancing swarms?

MonkeezOnFire · Apr 30, 2019

I might add a condition that the swarm only gets advantage to attack rolls against creatures of the swarm's size or smaller. I don't see them being as effective against something that they can't effectively surround. Multiattack makes perfect sense and would be a good way to up challenge the lower level swarms we currently have.

Inflicting conditions like grappled or restrained on a hit could make sense to model having a large number of creatures weighing you down. There are plenty of monsters that automatically get grappled on a successful attack to set the precedent.

jayoungr · Apr 30, 2019

Remember that you can have multiple swarms attack. Last weekend in one of my games, a party of four level 3 adventurers got really torn up by 5 rat swarms.

robus · Apr 30, 2019

jayoungr said:
Remember that you can have multiple swarms attack. Last weekend in one of my games, a party of four level 3 adventurers got really torn up by 5 rat swarms.

Yep - I do plan for that as well, but at level 1 that seems a bit much. I just wanted the bats (in this case) to be at least a little threatening

LordEntrails · Apr 30, 2019

The damage output of a swarm already varies based on if they half more or less than half HP. So adding multiattack just exaggerates this. All you have done is half the damage but double the number of attacks, which is most cases comes out the same. Is that worth it?

You could add overwhelming, but why? Just because you feel they should be tougher? The ability to hit is represented by their attack bonus. Giving them advantage (while I have no problem with it) just effectively ups they attack bonus. Maybe them having advantage might offset some disadvantage situations...? But would also prevent other situations that give them advantage.

So, in short, MA and damage change doesn't effect anything so why bother? Overwhelm might be fine, but all that for what gain?

Usually when I use swarms, there is not just one of them, but mayhaps a dozen. You know, each character gets there own and then after you disperse one, a round or two later more form. Yes it can make combat take more than 3 rounds, but it gives the players a real since of being swarmed and heightens the fear because they never know when they are actually going to drive off the swarm.

robus · Apr 30, 2019

MonkeezOnFire said:
I might add a condition that the swarm only gets advantage to attack rolls against creatures of the swarm's size or smaller. I don't see them being as effective against something that they can't effectively surround. Multiattack makes perfect sense and would be a good way to up challenge the lower level swarms we currently have.

Well given their high dexterity it seems it's more a matter of being hard to defend against because they're all over the place and moving quickly?

Inflicting conditions like grappled or restrained on a hit could make sense to model having a large number of creatures weighing you down. There are plenty of monsters that automatically get grappled on a successful attack to set the precedent.

Yep, definitely for things like zombie swarms that's good. I guess the big thing for me is the lack of advantage on attacks. Why should a pack get it and not a swarm?

robus · Apr 30, 2019

LordEntrails said:
The damage output of a swarm already varies based on if they half more or less than half HP. So adding multiattack just exaggerates this. All you have done is half the damage but double the number of attacks, which is most cases comes out the same. Is that worth it?

I just changed the logic a little is all. I used the lower damage output from the original but gave it two chances to hit.

LordEntrails · Apr 30, 2019

robus said:
I just changed the logic a little is all. I used the lower damage output from the original but gave it two chances to hit.

I got that, but why? The max damage is the same, you've just increased the odds of at least one hit, but you have doubles the number of attack rolls. Is that increased average DPR worth the effort?

Oofta · Apr 30, 2019

We are talking about a monster with CR 1/4, right? I have no problem with upping damage potential or just throwing multiple swarms (a swarm of swarms?) but I'd double check expected HP and damage potential against similar monsters.

I modify monsters all the time, but I'm also careful to recalculate CR when I'm done, a single CR 1/4 monster should be an easy fight for your average level 1 party.