Stinger (CR 4)

Large Monstrous Humanoid
Alignment: Usually neutral evil
Initiative: +6 (+2 Dex, +4 improved initiative); Senses: tremorsense, darkvision 60 ft., Listen +3, and Spot +2

AC: 15 (-1 size, +2 Dex, +4 natural), touch 11, flat-footed 13
Hit Dice: 4d8+8 (26 hp)
Fort +3, Ref +6, Will +4
Speed: 30 ft.
Space: 10 ft./5 ft. (10 ft. with stinger and spiked chain)
Base Attack +4; Grapple +11
Attack: Stinger +6 melee, 2 claws +1 melee; or Huge spiked chain +6 melee, stinger +1 melee
Full Attack: Stinger +6 melee, 2 claws +1 melee; or Huge spiked chain +6 melee, stinger +1 melee
Damage: Stinger 1d6+3 and poison, claw 1d6+1; or Huge spiked chain 2d6+3, stinger 1d8+1 and poison
Special Attacks/Actions: Poison
Abilities: Str 16, Dex 14, Con 14, Int 10, Wis 10, Cha 12
Special Qualities: bolthole magic
Feats: Exotic Weapon Proficiency (spiked chain); Improved Initiative
Skills: Hide +1, Listen +3, Move Silently +4, Search +2, Spot +2, and Survival +2
Advancement: By character class
Climate/Terrain: Temperate and warm desert, mountains, and underground
Organization: Solitary, recon (2), patrol (4), diviners (8), or city (50-1,000)
Treasure/Possessions: Standard

Source: Monster Compendium: Monsters of Faerûn

Poison (Ex): Stinger, Fortitude save (DC 14); initial and secondary damage 1d6 points of temporary Strength damage.

Tremorsense (Ex): Stingers can automatically sense the location of anything within 60 feet that is in contact with the ground.

Bolthole Magic (Sp): A stinger can move 20 feet straight up or straight down, so long as it passes through at least a foot of earth during its movement. For every 5 feet (or fraction thereof) of earth the stinger moves through, it suffers 1d3 points of damage. If a stinger's planned movement would place it inside a solid object, it remains in place but suffers the damage as if it had moved through the intervening earth. Stingers use their bolthole magic to move between previously prepared tunnels and the surface above, or sequences of tunnels, stacked one beneath the other. Use of this ability produces a flash of red light and a smell like that of burning insect skin.

Feats: Stingers have Improved Initiative as a bonus feat.

Stingers' tremorsense, bolthole magic ability, and excellent initiative frequently enable them to get in the first strike in any combat encounter. They hope to weaken their enemies with their poison sting.