The Sleeper was an ancient creature native to the depths Dathomir. Sporting two large lavender-colored eyes, a carapace-covered body, antennae, and four appendages, the upper pair resembling sickles with spearlike points while the lower appendages were actually tentacles, the Sleeper preferred to remain dormant in the subterranean pools below the Nightsister lair, emerging only when an aspiring Nightsister summoned it from the depths. The Jedi Master Quinlan Vos and the bounty hunter Asajj Ventress encountered the Sleeper while training to assassinate the Sith Lord Count Dooku.