Giant spiders is a large variant of the spider species.
—From Codex entry: Giant Spider
They typically appear in small numbers, but have been known to gather into larger groups for ambushes. Their primary ability allows them to throw their webbing, causing the victim to become encased and immobilized unless they pass a resistance check. Spiders can also use the Overwhelm ability, wherewith the spider tackles its victim, repeatedly inflicting physical damage and stunning the target for the remainder of the attack.
The party members should support each other whenever spiders arrive. If you end up apart, a spider's web or Overwhelm attack can incapacitate a lone companion. When webbed, the companions who aren't trapped should defend their comrade. Against an Overwhelm attack, everyone else should immediately focus on the charging spider to kill it before it kills your companion.
Both their Web and Overwhelm abilities are quite hard to resist, particularly the latter which keeps the target knocked down and taking serious damage for a few seconds (while additionally vulnerable to damage from other sources). Although Spiders use their abilities relatively rarely and chaotically, they sometimes happen to spontaneously chain them in a nasty way. Two inconspicuous Spiders chaining two Overwhelms in a row with a Web in between can even kill a lower-level warrior in the lower levels, whilst not giving him a split second to do anything at all. Quicksave your game before going against these creepy-crawlies.
- Some sources suggest that giant spiders were once raised by dwarves as a form of biological control for the many species of large bats that were endemic to the thaigs and Deep Roads. However, as the thaigs fell and the Deep Roads were abandoned, their populations exploded as a result of a plentiful new food source: darkspawn. Today they have spread throughout the Deep Roads and even spilled into caverns and forests on the surface.