A Doom-Joust was a deadly competition made popular on the planet, Serphidi in the Belial system. For centuries, the jousting competition on Serphidi was a ceremonial sporting event intended to entertain the masses. With the rise of the monarch, King S'Shah however, the spirited event evolved into a deadly war game.
S'Shah declared that the only legal means by which he could be overthrown from his position as king/monarch was if someone could best him in the Doom-Joust. An aging Serp named Elglih volunteered to face S'Shah in the competition, but eventually rescinded the challenge citing that he was too weak and infirm to successfully compete. Rebel Alliance commander, Luke Skywalker, agreed to take Elglih's place in the tournament. He successfully defeated S'Shah thus removing him from office. S'Shah attempted to kill Skywalker following his defeat, but Luke managed to fire a blast from a laser-lance at the Serp, killing him.
The rules governing the Doom-Joust were simple. The contest required two opponents positioned at opposite ends of a long field track to advance towards one another seated atop a two-legged lizard-mount. Each opponent was armed with a long, laser-lance that could project bolts of energy at a contestant's adversary. To win the competition, a contestant had to successfully unseat his or her opponent either by blasting them with the lance's energy capabilities, or by spearing them with the weapon's tip. A fatal strike was not required to win the contest, but was almost always expected.