Big "F"ing bug

Hellwidow

CR 8                                                                                                                  XP: 4,800

LE Large magical beast (extraplanar)
Init +7; Senses darkvision 60 ft., low-light vision, tremorsense 60 ft.; Perception +8
AC 22, touch 12, flat-footed 19 (-1 size, +10 natural, +3 Dex)
HP 95 (10d10+40)
Fort +13, Ref +12, Will +5
Defensive Abilities venom resistance; DR 10/silver; Immune fire; Resist acid 10, cold 10
Speed 40 ft., climb 30 ft.
Melee bite +16 (2d8+10 plus 1d6 fire and poison)
Space 10 ft., Reach 5 ft.
Str 24, Dex 17, Con 18, Int 7, Wis 15, Cha 12
Base Atk +10; CMB +18; CMD 31
Feats Great Fortitude, Improved Initiative, Lightning Reflexes, Skill Focus (stealth), Weapon Focus (bite)
Skills Climb +22, Perception +8, Stealth +8
Languages Infernal (can’t speak)
Environment any (Nine Hells)
Organization solitary, pair, or gang (3–6)
Treasure incidental
Fiery Webs (Ex) The hellwidow can set any of its webs on fire as a free action at the start of its turn merely by touching the webbing. Creatures caught in the webs when they catch fire take 2d6 points of fire damage each round until they escape. After escaping, creatures continue taking this damage each round unless they succeed on a DC 15 Reflex save. A new save can be made each round to extinguish the fire.
Poison (Ex) Bite—injury; save DC 23 Fort; frequency 1/round for 6 rounds; effect 1d4 Constitution damage plus 1d6 fire damage and staggered; cure 2 saves. The save DC is Constitution-based and includes a +4 racial bonus.
Venom Resistance (Ex) Hellwidows gain a +4 racial bonus on saving throws against spider venom.
This massive long-legged giant spider is crimson in color with dull red, barely visible, hourglass-shaped markings on its underside.
Hellwidows are roughly 9 feet long and weighs nearly 1,000 pounds, with males being slightly smaller than females.
Hellwidows are giant spiders that make their home within the Nine Hells. They are believed to be the result of diabolical experiments that crossed giant black widows with devils. These creatures, while possibly related to black widows, are much more cunning and intelligent. Hellwidows dwell on the warmer planes of Hell’s layers, generally avoiding the colder lower planes. Giant web-filled caverns serve as their lairs. When encountered on the Material Plane, it is most often in thick forests or caverns in warmer climates. Evil spellcasters occasionally summon a hellwidow to the Material Plane and strike a bargain with the creature offering food, treasure, or the like in return for some service (usually guarding a location or killing a particular enemy).
Hellwidows mate several times per year with the female laying up to 100 eggs in a single dull gray egg sac. The eggs hatch within 30 days, with only about 25% of the young surviving. Young are blood red in color with dull yellow stripes on their abdomens. Young mature rapidly, reaching adulthood within six months.
Hellwidows are carnivores and prey on various types of other creatures, including lesser devils, fiendish insects, and even other hellwidows. Prey is quickly cocooned in the hellwidow’s webbing, set on fire, and then bitten repeatedly until it succumbs to the widow’s poison. Once the prey is dead, the hellwidow carries it back to its lair to be devoured. Hellwidows prefer to hunt by ambush; usually hiding in dark corners within their webs. When they detect movement, such as a creature becoming entangled in their webs, they quickly move to strike.
Source: Tome of Horrors 4