Spider, Harpoon (CR 4)

Large Aberration
Alignment: Usually chaotic evil
Initiative: +4 (Dex); Senses: darkvision 120 ft. and Spot +7
Languages: Common and Undercommon

AC: 16 (-1 size, +4 Dex, +3 natural), touch 13, flat-footed 12
Hit Dice: 5d8+20+5 (47 hp)
Fort +5, Ref +5, Will +5
Speed: 40 ft., climb 20 ft.
Space: 10 ft./5 ft.
Base Attack +3; Grapple +10
Attack: Bite +5 melee or fang +6 ranged
Full Attack: Bite +5 melee or 2 fangs +6 ranged
Damage: Bite 1d8+3 plus poison, fangs 1d4+1 plus harpooning
Special Attacks/Actions: Harpooning, poison
Abilities: Str 17, Dex 19, Con 18, Int 14, Wis 12, Cha 9
Special Qualities: evasion, spines, web movement
Feats: Combat Reflexes; Improved Toughness; Improved Trip
Skills: Balance +8, Climb +16, Hide +8, Jump +21, Spot +7, and Tumble +11
Advancement: 6-8 HD (Large); 9-15 HD (Huge)
Climate/Terrain: Underground
Organization: Solitary, pair, or nest (2-5 plus 1-2 ettercaps and 2-4 Medium monstrous spiders)
Treasure/Possessions: Standard

Source: Monster Manual III

Harpooning (Ex): as ranged attacks, a harpoon spider can fire one or two of its fangs up to 20 feet (no range increment). The spider can fire at two different targets if it chooses. A successful hit deals 1d4+1 points of damage as the harpoon hooks the flesh of the target and immediately exudes a thick, sticky glue. The spider can reel in a harpoon as a free action; treat this as a trip attack (+10 bonus) against any creature attached to the fang. Failure indicates that the harpoon rips free (and deals another 1d4+1 points of damage to the victim). Success indicates that the victim is pulled off its feet and dragged back to the spider, who can immediately make a free bite attack against the victim. A harpoon spider can only pull a creature smaller than itself in this manner. Attempts to retract a creature of its own size or larger automatically cause the fang to rip free as if the trip attack failed. The glue exuded by the spider's fangs decomposes quickly, and at the end of the spider's turn the fang automatically detaches.

Poison (Ex): injury, fortitude DC 16, initial damage 1d6 Dex, secondary damage 2d6 Dex. The save DC is constitution-based.

Spines (Ex): Any creature striking a harpoon spider with its body or a handheld weapon must make a DC 16 reflex save or take 1d6 points of piercing damage from the spider's spines. (Creatures wielding reach weapons, such as longspears, are not subject to this damage.) The spines also deal an extra 1d6 points of damage on a successful grapple check (much like armor spikes). The save DC is dexterity-based.

As a full-round action, a harpoon spider can pick up a medium or smaller helpless creature with its legs and impale the body on its spines, dealing 2d6 points of piercing damage. The spider can carry up to 2 medium, 8 small, 32 tiny, or 128 diminutive or smaller creatures in this manner. Harpoon spiders often use this method to carry their next meals.

Web Movement (Ex): Although they cannot spin webs themselves, harpoon spiders can climb around and through webs with ease using their climb speed. They are immune to the effects of the web spell.

skills: a harpoon spider has a +8 racial bonus on climb checks and jump checks, and it can always choose to take 10 on a climb check, even if rushed or threatened.

Feats: a harpoon spider gains improved trip as a bonus feat, even though it does not meet the prerequisites.

A harpoon spider is a hunter, often stalking victims in a large territory around its lair. In combat, it uses its harpoon fangs and improved trip feat to reel in prey, then administers a bite once its opponent has been brought close. If the terrain permits, the spider prefers to attack victims from high vantage points (such as ledges).