Encounters: Anauroch - The Sword - Deep Desert (Night)

Swarm, Centipede (CR 4)

Diminutive Vermin (Swarm)
Alignment: Always neutral
Initiative: +4 (Dex); Senses: darkvision 60 ft., tremorsense 30 ft., and Spot +4

AC: 18 (+4 size, +4 Dex), touch 18, flat-footed 14
Hit Dice: 9d8-9 (31 hp)
Fort +5, Ref +7, Will +3

Speed: 20 ft., climb 20 ft.
Space: 10 ft./0 ft.
Base Attack +6; Grapple -
Attack: Swarm
Full Attack: Swarm
Damage: Swarm 2d6 plus poison
Special Attacks: Distraction, poison

Abilities: Str 1, Dex 19, Con 8, Int -, Wis 10, Cha 2
Special Qualities: immune to weapon damage, swarm, vermin
Feats: Weapon Finesse
Skills: Climb +2 and Spot +4
Advancement: -

Climate/Terrain: Underground
Organization: Solitary, tangle (2-4 swarms), or colony (11-20 swarms)
Treasure: None

Source: Monster Manual

Distraction (Ex): Any living creature that begins its turn centipede swarm in its space must succeed on a DC 13 Fortitude save or be nauseated for t round. The save DC is Constitution-based.

Poison (Ex): Injury, Fortitude DC 13, initial and secondary damage 1d4 Dex. The save DC is Constitution-based.

Skills: A centipede swarm has a +4 racial bonus on Spot checks and a +8 racial bonus on Climb checks, and uses its Dexterity modifier instead of its Strength modifier for Climb checks.

A centipede swarm has a +8 racial bonus on Climb checks and can always choose to take 10 on a Climb check, even if rushed or threatened.

A centipede swarm seeks to surround and attack any living prey it encounters. A swarm deals 2d6 points of damage to any creature whose space it occupies at the end of its move.

Faerûnian Random Encounters by Region and Locale