The "Dragon" was birthed from Spike, a prison dog that was impregnated by a facehugger. The Runner violently emerges out of the dog, coincidentally during the funeral for Newt and Corporal Hicks, who were both killed when the escape pod crashed on Fiorina 161. The "Dragon" took residence in the prison's air ducts while it matures and where it claimed its first victim, a prisoner named Thomas Murphy, who was cleaning the air ducts. Murphy hears noises coming from a hole in the wall, and goes to investigate, believing it to be his dog, Spike. He soon realizes it is not his pet, but the juvenile alien. Before he can pull his head out of the hole, the alien spits acid into his face. He stammers backwards in agony and accidentally tumbles into a large spinning fan, killing him instantaneously.
After the "Dragon" had reached its mature state, it begins a killing spree by killing prisoners Boggs and Rains while being witnessed by fellow prisoner Golic, which caused him to be obsessed with the creature and dubbed it by it's nickname. The Runner then went the the prison's infirmary and killed Clemens, it confronts Ellen Ripley but spares her as it sensed the Queen chestburster within her. It later causes further pandemonium as it killed warden Andrews in front of everyone in the mess hall. Due to the absence of weapons in the prison, Ripley rallies the inmates and proposes they pour highly flammable toxic waste, which is stored at the facility, into the ventilation system and ignite it to flush out the creature. An explosion is caused by the Runner's premature intervention, resulting in several deaths.
The remaining survivors later form a plan to lure it into the foundry's molding facility and drown it in molten lead. The bait-and-chase style plan results in the death of nearly all the remaining prisoners, leaving only Ripley, Dillon and Morse left alive. Dillon nobly faces the "Dragon", hoping to stall it long enough for Ripley and Morse to pour the lead. After killing Dillon, the "Dragon" was drowned in molten lead. The "Dragon", now covered in molten metal, leaps from the mold and tries to kill Ripley, but was ultimately killed by her when she turned on the fire sprinklers and sprayed the creature with water, causing its exoskeleton to cool rapidly and shatter via thermal shock.