"Dragon" was the name given to the Xenomorph antagonist of Alien 3. This creature was born from a canine host on the planet Fiorina 161 where it went on a killing spree before being slain by Ellen Ripley. It was portrayed by Tom Woodruff, Jr.
The Dragon began its life as one of two parasitic embryos produced by a Royal Facehugger. The Facehugger had hatched from an egg that had been smuggled aboard the USS Sulaco by the Xenomorph Queen from LV-426. While the queen had been jettisoned into space, the egg had gone unnoticed and hatched while Ellen Ripley, Dwayne Hicks, Newt and Bishop were in cryostasis. The Facehugger went wandering around the ship, causing an electrical fire as it searched for a potential victim.
The Facehugger entered the hypersleep chamber aboard the Sulaco's emergency escape vehicle where Ripley and the others were sleeping. The creature breached Ripley's cryotube and coupled with her face, implanting her with an embryonic queen. As this was happening, the escape pod was jettisoned and fell towards the nearby planet of Fiorina 161, the site of a Weyland-Yutani foundry and prison complex. The pod came down hard and Hicks' and Newt's cryotubes were damaged, resulting in their deaths. However, Ripley and the Facehugger survived. Before Ripley was found and recovered by the prison inmates, the Facehugger had let go of her. Unlike most Facehuggers which died after implanting a single embryo, this specimen remained alive and had another embryo yet to implant. Not long after Ripley was pulled from the pod, the prison dog Spike caught the scent of the Facehugger. The parasite attacked the dog and latched onto its head, impregnating it before it let go and died.
A few short hours later, the Xenomorph within Spike's body matured and tore its way out. Unlike Xenomorph drones born from humans, this specimen was not serpentine upon birth, sporting a full set of limbs; it had digitigrade legs and was more suited for running on all fours. The newborn creature then fled into the dark recesses of the prison, hiding away in a ventilation shaft while it grew to its adult phase. By the time it had fully grown, it was discovered by inmate Thomas Murphy. It spat acid in Murphy's face, causing him to tumble down the shaft towards a large fan which diced him to pieces. It later attacked and killed Boggs and Rains in an abandoned tunnel, though it was also witnessed by Walter Golic. Following this encounter, the mentally unstable Golic developed an obsessive fascination with the alien, referring to it as a "dragon".
Later, the Dragon killed medical officer Clemens in the infirmary. It also encountered Ripley, but could sense that she was carrying a queen embryo inside her and so it left her alone, fleeing back into the air duct from whence it came. Because the monster had spared her, Ripley grew concerned enough to conduct a bioscan on herself, revealing that she was hosting a queen. She attempted to alert the other prisoners about the Xenomorph running loose, but Superintendent Andrews stepped in to quash what he considered to be unsubstantiated rumours. However, it was then that Andrews became the Dragon's next victim, with all the remaining prisoners being there to see it.
Without any kind of weaponry in the prison, Ripley and the inmates devised a plan to use quinitricetyline to create a fire and hopefully drive the Dragon into a disused nuclear waste tank where it could be contained. However, the creature prematurely intervened and attacked Frank, causing him to drop his detonator onto the quinitricetyline. The massive explosion resulted in the deaths of several prisoners, while the Dragon itself escaped.
In an act of desperation, the remaining prisoners concocted a plan to lure the Dragon into the old lead works and drown it in molten lead. Using themselves as live bait, the prisoners were able to draw the alien towards the mold, though this ultimately cost the lives of every prisoner except for Robert Morse. Leonard Dillon fought the Dragon directly, keeping it inside the mold while Ripley got out and activated the feed switch. Dillon was killed, but the plan worked and the Dragon was submerged in boiling hot lead.
Remarkably, however, the creature survived the ordeal and it leapt from the mold, now covered in molten metal and intent on killing Ripley. As it approached, Ripley activated the fire sprinklers overhead, and the resultant deluge of cold water caused the Dragon's mesoskeleton to explode through thermal shock.