Chelicera (CR 6)

Medium Vermin
Alignment: Always neutral
Initiative: +4 (Dex); Senses: darkvision 60 ft., scent, and Listen +9

AC: 19 (+4 Dex, +5 natural), touch 14, flat-footed 15
Hit Dice: 12d8+12 (66 hp)
Fort +9, Ref +8, Will +5
Speed: 30 ft., climb 30 ft.
Space: 5 ft./5 ft.
Base Attack +9; Grapple +17
Attack: Claw +13 melee
Full Attack: 2 claws +13 melee and bite +8 melee
Damage: Claw 1d6+2, Bite 1d8+1
Special Attacks/Actions: Blood drain, improved grab
Abilities: Str 14, Dex 19, Con 12, Int -, Wis 13, Cha 12
Special Qualities: immunity to sonic, mimicry, vermin traits
Feats: Weapon Finesse
Skills: Climb +10, Hide +12, and Listen +9
Advancement: 13-16 HD (Medium); 17-36 HD (Large)
Climate/Terrain: Warm mountains
Organization: Solitary or pack (2-8)
Treasure: Standard

Source: Monster Manual III

This creature looks like a spindly black spider as large as a human. Two thin arms extend from the insect's small body, each ending in a sharp looking claw. A strange pair of thick antennae sits atop its head like a tuningfork.

The chelicera is a spidery creature that can reproduce any sound it hears. Cheliceras are a common problem in towns and cities built in warm climates, where the vermin tend to live in neighborhoods with poor sanitation.

A chelicera can remember and duplicate sounds. It has no understanding of speech, but can duplicate many of the component sounds. The creature rests each sound it knows, looking for those that most reliably draw prey. Often, the most useful sounds are the screams of a previous victim.

From their hidden lairs, they lure victims to their doom by reproducing the sounds they hear. Warriors of noble intent rush into a chelicera's lair to rescue an innocent, only to discover that it is they who need rescuing. Once someone enters a chelicera's territory in search of the source of the sounds, the creature attacks, leaving the drained corpse in another part of town. Infestations are often mistaken for the work of a vampire, but holy water and garlic is of no use against the cheliceras.

A chelicera is mostly long legs and arms, standing 4 feet tall and about 5 feet in diameter even though its body is only about the size of a full backpack. It weighs no more than 50 pounds.