Swarms give me a headache - trying to create one

[Ryuugan]

I have a game starting next wednesday and I still need to figure out stats for one of my own critters. I call them gnarkis, and they're tiny magical beast swarms. One gnarki is like a black ball of fur, with poisonous teeth (str-damage), and several limbs to grab effectively.

I was thinking that the swarm should be CR 6 and be mostly annoying to the characters. This is what I've come up this far:

Gnarki CR6
Tiny magical beast swarm
Darkvision 60ft
HP 65 (10d10+10)
Init +10 AC: 20 (+6 Dex,+2 natural,+2 size)Touch 18, flat-footed 12
Skills: Climb +16 Swim +8

STR 6 DEX 22 CON 12 INT 6 WIS 14 CHA 2

BAB +10 CMB +16 CMD 22

Fort +8 Ref +13 Will +5

Offense:
Swarm 3d6 + Gnarki poison + grapple (Fortitude save DC 16 (constitution
based))

Speed 35ft Space 10ft Reach 0ft

Special
Gnarkis get +8 racial bonus to grabble and climb checks

Gnarki poison effects immediately for 6 rounds with d3 strength damage each round. DC 16 to save

Feats Improved grabble, Improved natural armour, improved natural attack, Improved initiative, Fleet

What do you think? Too much for a CR 6?

[Kelso]

In my opinion you should lower the CR to 4 or 5. I don't know, it seems too easy for 6.

Since it's tiny, the PCs will be able to do half damage with weapons. Plus if the arcane caster knows burning hands, this is a one round encounter. The poison could be a pain and all, but if the PCs are careful, they'll never even take damage.

I'm not trashing it, by the way, I think it's a cool monster.

One other thing, there's no point to the racial grapple bonus and having CMD and CMB values. Swarms don't get those things, ordinarily.

[Ryuugan]

The party consists of a rogue, monk and a druid. They all are at 5th level.

The idea behind the grabble is kind of a special attack. Gnarkis' combat strategy is pretty much to hunt down their prey, attach themselves to it and wait till it dies.

Maybe I should add bleed damage if the grabble holds?

[Kelso]

If I understand correctly. This is a swarm of tiny fuzzballs with teeth that move quickly and swarm onto their prey. Since you're letting them have Grappling and they've got a good CMB, then Yes, this is pretty tough for CR 6. With 3 level 5 characters, I think this could easily turn into a TPK, if all 3 characters are standing together so that it can swarm, immobilize and poison all 3 characters at once.

I would say your monster here is more powerful than an Ettin (CR 6, same hp as yours). Maybe more powerful than a Dragonne (CR 7.) Probably less powerful than an efreeti (CR 8.)

I don't recall if the Druid has any decent area attacks at that level. That would make a big difference.

[Ryuugan]

I weakened the thing a bit

Gnarki CR6
Tiny magical beast swarm
Darkvision 60ft
HP 52 (8d10+8)
Init +10 AC: 20 (+6 Dex,+2 natural,+2 size)Touch 18, flat-footed 12
Skills: Climb +12 Swim +8

STR 6 DEX 22 CON 12 INT 6 WIS 14 CHA 2

BAB +8 CMB +8 CMD 20

Fort +7 Ref +12 Will +4

Offense:
Swarm 2d6 + Gnarki poison + grapple (Fortitude save DC 15 (constitution
based))

Speed 35ft Space 10ft Reach 0ft

Special
Gnarkis get +4 racial bonus to grabble and climb checks

Gnarki poison effects immediately for 4 rounds with 1d3 point strength damage each round. DC 15 to save

Feats: Improved grabble, Improved natural armour,Improved initiative, Fleet