The Sic-Six were a species of intelligent arachnids who could produce webbing and use it to detect nearby presences by hearing the vibrations of the threads. Their proportionally large tympanic membranes, which covered most of their bodies, made this possible. At the same time, this made them vulnerable to loud sounds. Sic-Six had other important sensory organs, including four pairs of eyes, each adapted to see a different part of the spectrum.