Space Caterpillars are a species of alien animals encountered by Pidge in a trash nebula.
The caterpillars are small aliens that live in large colonies; individuals are covered in fur that is either bright blue, pink, green, or yellow in color. Their tan underbellies are the exception, being furless and segemented, lined with eight tiny red legs. Each caterpillar has a pair of large eyes with a visible pupil white sclerae, but they are never seen blinking. The species is capable of maneuvering through areas of zero gravity and clinging to objects to avoid floating.
Caterpillars have a small mouth and the inside is never seen. On either side of their mouths is a pair of triangular markings, curving upward and outward, that appears to glow in light blue. These markings increase in luminescence for communication, flashing as an alerting signal. The species seems somewhat understanding of common speech, as they understood Pidge when she mentioned "friends".
- The species may have the ability to detect technological energy or Quintessence, as they noticed the Green Lion reawakened before Pidge realized.