Illithocyte (CR 2)

Small Aberration
Alignment: Always Neutral
Initiative: +1 (Dex); Senses: darkvision 60 ft., lifesense, Listen +4, and Spot +4

AC: 14 (+1 size, +1 Dex, +2 natural), touch 12, flat-footed 13
Hit Dice: 4d8 (18 hp)
Fort +1, Ref +2, Will +5
Speed: 20 ft.
Space: 5 ft./5 ft.
Base Attack +3; Grapple -2
Attack: Tentacle +5 melee
Full Attack: 4 tentacles +5 melee
Damage: Tentacle 1d2-1
Special Attacks/Actions: Swarmfighting
Abilities: Str 8, Dex 13, Con 11, Int 2, Wis 12, Cha 6
Special Qualities: resistance to acid 20, SR 13, telepathic link, vulnerability to fire
Feats: Blind-fight; Weapon Finesse
Skills: Escape Artist +2, Hide +5, Listen +4, and Spot +4
Advancement: 5-12 HD (Small)
Climate/Terrain: Underground
Organization: Mass (3-30)
Treasure/Possessions: None

Source: Dragon #337

Swarmfighting (Ex): Illithocytes can coordinate melee attacks against a single target and are adept at fighting side by side in close quarters. An illithocyte can occupy the same 1-foot square in combat with any other illithocyte at no penalty. When an illithocyte engages a Medium or larger creature in melee, and at least one other illithocyte threatens the target, it gains a +1 morale bonus on the attack roll. This bonus increases by +1 for each additional illithocyte beyond the first that threatens the same target.

Lifesense (Su): An illithocyte continually detects the presence of living creatures within 30 feet. Although this ability pinpoints the location of living creatures, it does not grant any bonuses against concealment, invisibility, or total cover.

Telepathic Link (Ex): Illithocytes share a communal consciousness, enabling them to communicate telepathically with other creatures of their kind. A group of such creatures within 100 feet of each other are in constant contact. If one is aware of a particular danger, they all are. If one in the group is not flatfooted, none of them are.

Illithocytes are aggressive, striking before adversaries can react. Groups of illithocytes direct their attacks against a single target, maximizing their ability to fight in close quarters. Being the chief source of nutrition for the ravening neothelids, illithocytes use their aggression to drive off these predators.