- "Efforts to transplant colonies of the energy spiders that produce the stuff haven't been very successful."
"You're trying to get them to survive on other planets?"
"Yes, but they just stop feeding and die—"
- ―Lando Calrissian and Han Solo, on Calrissian's efforts to expand glitterstim production
Energy spiders or spice spiders were arachnids that inhabited the spice mines of Kessel. They lived in complete darkness inside the mine's caves spinning webs made of glitterstim, a rare kind of spice. The spiders would shoot webbing from their mouths to capture prey, impale them and then quickly suck the life energy from them. The spiders were known to feed on bogeys, as they were sources of pure energy that caused the glitterstim to react and produce light, alerting the spiders to their presence. The spiders also disliked bright light, since they lived in pitch black caves. Energy spiders were, however, drawn to the light produced by the glitterstim-bogey interaction, and there are even cases of mistaking other lighting sources for this interaction. They were one of the many threats faced by the spice miners, especially those who wandered too deep into the caves where the spiders lived. Often, the administrators and superiors on Kessel would send disruptive prisoners to work in these deep tunnels, ensuring an often permanent solution to a prisoner problem. As energy spiders feed on energy, blaster bolts are ineffective against them and are merely absorbed. Curiously, ion weapons, since they affect energy and its distribution, are highly effective (but not lethal) against them.
A variant sub-species of energy spider was discovered by Han Solo and Leia Organa Solo while investigating a series of ground quakes on behalf of Lando Calrissian, owner of the spice mining operation. The newly discovered subspecies had a reddish hue and lacked the hooks and spines that are present on the arms of typical spiders. These "red spiders" were found to be herbivorous, feeding on the giant fungi found in the lower reaches of Kessel's spice mines. These red spiders had a poisonous effect on baseline energy spiders, allowing the two to coexist. Genetically, the two different types could even mate, though no documentation of the act nor results existed.
When fed ryll, the energy spiders would produce glitteryll and grow to large sizes. A number of the creatures were smuggled onto Ryloth, which proved to be one of the few other worlds capable of supporting them. A few made their way to Coruscant for the Coruscant Livestock Exchange and Exhibition following the establishment of the New Republic in its arthropod exhibit, along with toxin/adrenaline-producing orbalisks and Death Seed-producing drochs.
- Star Wars: Republic 20: Twilight, Part 2 (Mentioned only)
- Star Wars: Republic 21: Twilight, Part 3
- Star Wars: Republic 22: Twilight, Part 4 (Mentioned only)
- Star Wars: Purge (Mentioned only)
- Star Wars: Empire at War (Mentioned only)
- Star Wars: Empire at War: Forces of Corruption (Mentioned only)
- "Buyer's Market"—Star Wars Insider 126 (Mentioned only)
- Jedi Search (First appearance)
- Champions of the Force
- The New Jedi Order: Star by Star (Mentioned only)
- Millennium Falcon (Mentioned only)
- Fate of the Jedi: Outcast
- Fate of the Jedi: Conviction (Mentioned only)
- "The Unseen Planets of Star Wars"—Star Wars Insider 36
- The Essential Guide to Planets and Moons
- The Essential Guide to Alien Species
- Alien Anthology
- Geonosis and the Outer Rim Worlds
- The Wildlife of Star Wars: A Field Guide
- The Jedi Academy Sourcebook
- Star Wars: Empire at War: Forces of Corruption: Prima Official Game Guide
- Scum and Villainy
- The Complete Star Wars Encyclopedia
- Star Wars: Edge of the Empire Core Rulebook