The Giant Spider is the strongest common variety of Spiders, mostly encountered during Baldur's Gate with only a couple potentially being spotted in Baldur's Gate II. They are almost always encountered within the depths of a forest, particularly during waylaid encounters between such areas, and are distinguishable from their brethren by way of a green body with grey legs - pointedly different from the more powerful Phase Spider.
Like most spiders, they can Poison their enemies and are immune to Web. They are essentially a step up from the Huge Spider, while not yet evolving any special abilities often found among the higher-tiered spiders. They also have a relatively low mobs-per-spawn rate, with a high level party only ever encountering as many as two, comparable in this regard to the Cave Bear or Wraith Spider while pointedly being worth significantly less experience than either.