Chainworm (CR 2)

Large Vermin
Alignment: Always neutral
Initiative: +3 (Dex); Senses: light blindness, darkvision 60 ft., Listen +2, and Spot +3

AC: 15 (-1 size, +3 Dex, +3 natural), touch 12, flat-footed 12
Hit Dice: 3d8 (13 hp)
Fort +3, Ref +4, Will +1
Speed: 30 ft., climb 20 ft.
Space: 10 ft./5 ft.
Base Attack +2; Grapple +1
Attack: Bite +2 melee; or sting +2 melee
Full Attack: Bite +2 melee; or sting +2 melee
Damage: Bite 1d6+1; or sting 1d8+1 and poison
Special Attacks/Actions: Poison
Abilities: Str 13, Dex 16, Con 10, Int -, Wis 10, Cha 2
Special Qualities: Vermin, web
Feats: -
Skills: Climb +8, Hide +1, Listen +2, and Spot +3
Advancement: 4-7 HD (Large); 8-9 HD (Large)
Climate/Terrain: Any underground
Organization: Solitary, gang (2-4), or nest (5-10)
Treasure: None

Source: Converted

A chainworm appears as a silver-scaled caterpillar 8'-10' long with a razor sharp barb on its tail.

A chainworm can spin a web that covers an area of 5 ft. by 5 ft. in one round. Chainworms do not spin these webs at victims, rather they cover an area and wait for prey to become trapped in the near metal strength strands. Once trapped, a chainworm moves in and attacks its prey.