The Sith wyrm was a massive creature that lived on the the fourth moon of Yavin in large subterranean lairs.
The ancient Massassi worshiped the beast as a god until it was killed by Exar Kun a millennia later, who did so to impress the spirit of Freedon Nadd. It was learned later that the creature was originally an infant exogorth that had attached itself to Sadow's battleship. However it is evident that there was more than one in the galaxy.
Sith wyrms eventually lived up to the Clone Wars, with Darth Sidious briefly allowing a smaller Sith wyrm to eat his blood before promptly devouring it as part of an arcane ritual to summon a storm across Coruscant. Shortly thereafter, he then summoned a gargantuan wyrm to devour him whole, only to destroy the wyrm from within, re-adopting the amiable appearance of Supreme Chancellor Palpatine.
- Tales of the Jedi: Dark Lords of the Sith
- Timeline 10: The Exar Kun War (Appears in hologram)
- The Dark Side Sourcebook
- Knights of the Old Republic Campaign Guide
- Jedi Academy Training Manual
- Book of Sith: Secrets from the Dark Side