Native to the planet Ruusan, the bouncers were a species of round-bodied, avian creatures that moved through air as if levitating. Their bodies were covered with greenish fur, and their long tails drifted behind them as they moved about. The face of a bouncer was formed of two wide eyes, and lacked any kind of nose or mouth. Innately intelligent, bouncers could not communicate vocally, but spoke to one another through a form of telepathy. This was simply a form of communication, and the bouncers could not actually read each other's minds. They were also attuned to the Force, and often had dreams which revealed images of the future. However, bouncers could also be killed by dreams that were too violent, and many died in this way in the months and weeks leading up to the Battle of Ruusan.
Those who survived were driven slowly mad, as they tried to offer comfort and support to the Jedi but were met only with pain and suffering, and many began attacking soldiers on both sides of the conflict in an insane effort to stop the madness. The Jedi Knights of the Army of Light were forced to kill many bouncers in what they believed was a humane action to put them out of their misery. Many natives of Ruusan believed that the bouncers never really forgot this, and held a grudge against the Jedi for many generations.
In the aftermath of the war between the Jedi and the Sith, the bouncers were all but destroyed. Those bouncers that survived told of a prophecy in which "…a Knight shall come, a battle will be fought, and the prisoners shall go free." Many believed that this prophecy referred to the souls of both the Jedi and the Sith that were killed by the thought bomb unleashed by the Brotherhood of Darkness, in the area that became known as the Valley of the Jedi. This prophecy was proven to be true when Kyle Katarn defeated Jerec and his Dark Jedi in the Valley, setting free the collected spirits.