An Octospider superficially resembles a giant spider in overall body plan, but the resemblance stops there. The main body is bulbous and fleshy, narrowing without seams to a kind of thick stalk at the bottom which then widens out into a flattened shape to which the eight legs are attached. The legs splay out to either side in a pattern very similar to that of an ordinary spider, but the legs are formed like the tentacular arms of an octopus, though shorter and thicker. The triangular pads on which they walk are covered with suction cups which allow them to climb vertical surfaces; they cannot, thankfully, cross ceilings or overhangs in this fashion. Two startlingly human-like eyes are positioned between the forelegs, with another eye between each other pair of legs including a single eye looking out from between the back legs. Finally, the octospider’s beak through which it both eats and breathes is located underneath the lower body.

Generally octospiders are grayish in color, mottled with small indistinct spots of tan, and their skin is moist like that of most other Nazgorean creatures.

Octospiders possess all the features and limitations of other Nazgorean creatures, such as resistance to mind-affecting spells, weakness to sunlight and dry air, and so on.