Bone gnashers were a breed of subterranean arachne native to the planet Endor. Bone gnashers were so called because they were able to rapidly strip the flesh off corpses.
During the Galactic Civil War, a pack of bone gnashers inhabited the Krayt Cult Cave near Mos Eisley. They had been transplanted from Endor to Tatooine, likely by the Krayt Cultists themselves.
Sometime following the Battle of Yavin in 0 BBY, a spacer was sent by Tori Radeen to kill bone gnashers in the Krayt Cult Cave, and bring back six poison glands. Tori Radeen used the glands to create a new poison for use by Jabba the Hutt.
Bone gnashers appeared in the 2003 video game Star Wars Galaxies, a massively multiplayer online roleplaying game developed by Sony Online Entertainment and published by LucasArts, prior to its closure on December 15, 2011. Bone gnashers were added to the game as part of the "Legacy Quest" with the release of the "Publish 25", a.k.a. the "New Game Enhancements," on November 15, 2005.