The Great Forest Spider is a large arachnid that resides in large forests. The great forest spider has adapted to digest plant matter. Due to this, the spider's primary diet consists of various trees and other large plants. The great forest spider will latch onto a tree, and begin shaking it until the tree falls over. The spider will then inject its venom into the fallen trunk and wait until the inside of the tree has become semi-liquid, then consumes the soupy mixture.

Great forest spiders rarely attack unprovoked, and often don't see people as a threat. Some spiders are passive enough to let people get close enough to pet them. When a great forest spider is attacked, they will defend their lives with full force, often requiring groups of 15-20 well-trained individuals to successfully take one down.

Great forest spiders have very few predators, but are often hunted by humans, mutants and ghouls. Killing a great forest spider is seen as a great feat in primitive or hunting-oriented cultures.