Encounters by Locale: Goblin Marches - Hills (Night)

Monstrous Spider, Huge (CR 5)

Huge Vermin
Alignment: Always Neutral
Initiative: +3 (Dex); Senses: darkvision 60 ft., tremorsense 60 ft., and Spot +4*


AC: 16 (-2 size, +3 Dex, +5 natural), touch 11, flat-footed 13
Hit Dice: 8d8+16 (52 hp)
Fort +8, Ref +5, Will +2
Speed: 30 ft., climb 20 ft.
Space: 15 ft./10 ft.
Base Attack +6; Grapple +18
Attack: Bite +9 melee
Full Attack: Bite +9 melee
Damage: Bite 2d6+6 and poison
Special Attacks: Poison, web
Abilities: Str 19, Dex 17, Con 14, Int -, Wis 10, Cha 2
Special Qualities: Vermin
Feats:
Skills: Climb +12, Hide +1*, Jump +4*, and Spot +4*
Advancement: 9-15 HD (Huge)
Climate/Terrain: Temperate forest
Organization: Solitary or colony (2-5)
Treasure: 1/10 coins, 50% goods, 50% items

Source: Monster Manual

All monstrous spiders are aggressive predators.

Monstrous spiders come in two general types; hunters and web-spinners. Hunters rove about, while web spinners usually attempt to trap prey. Hunting spiders are speedier than their web-spinning counterparts and use higher speed numbers shown in parentheses.

Monstrous spiders of both types have roughly circular bodies surrounded by outspread legs: 15 feet wide* and 2-1/2 feet high.
*The number includes the spider's body and its legs; the actual body diameter is about a third of the total.

Faerûnian Random Encounters by Region and Locale