Stalker (Earth-5875)

"I've seen the creature, what is it? I dunno, something brought here by Marlow, the captain of the Anesidora."

- - Amanda Ripley-McClaren and Marshal William Waits

The "Stalker" was a Xenomorph Lurker born aboard Sevastopol Station on December 6th, 2547 after the Anesidora crew member Catherine Foster was attacked and impregnated by a Facehugger. After its birth, the Stalker started terrorizing the station and killing most of its inhabitants.

Early life
The Stalker was born as one of the preserved Ovomorphs aboard a crash-landed forerunner vessel on the moon Acheron, orbiting the gas giant Calpamos, in the Zeta Reticuli system. Years in the past, the ship and its pilot crashed on the moon for reasons unknown, while the pilot became impregnated by a Facehugger. Before his death, the pilot sent a warning beacon in order to stop other potential settlers from arriving on the moon.

Birth
"I don't know what it is. Maybe a Covie species we never saw. Since that... thing appeared on Sevastopol, my team and I had been struggling to keep order."

- - Marshal William Waits to Amanda Ripley-McClaren On December 6th, 2547, the salvaging ship Anesidora investigated Acheron following the disappearance of the Weyland-Yutani Corporation freighter Nostromo seventeen years prior. When one of its explorers, Catherine Foster, found the derelict ship that the Covenant were excavating, she came close to one of the Ovomorphs, prompting a Facehugger to emerge and latch onto her face. After she was found, Foster was taken back to the Anesidora, where the Facehugger detached and died. Placed in cryosleep, she was brought to Sevastopol Station. After being observed by Dr. Kabira Lingard, Foster was instantly killed when a Chestbuster erupted from her chest, and which proceeded to kill Lingard. Growing in few minutes, the Stalker began an outbreak aboard the station, killing most of its inhabitants and causing massive panic. The Colonial Marshal William Waits and his teams attempted to control the situation, to no avail.

The Stalker eventually established a hive at the depths of the station, taking numerous hosts in order to form a Proto-Keymind.

Engineering
As the Stalker roamed through the station, it was spotted in engineering, prompting Waits and his men, Diego Turner, Deborah Garcia and Ridley Harris, sought to investigate. When they arrived, the team discovered two bloodied corpses and a locked door. As soon as Harris opened it, he was headbitten by the Stalker. This led Turner to charge at the xenomorph, but it acted faster and impaled the marshal with its tail. Waits and Garcia were then able to force the alien through the doorway with their M90 shotguns and closed it. The Stalker used this to its advantage, and preyed on both of them by using the vents. Garcia saw this and attempted to shoot the vents, but she was taken by the xenomorph before she could act react.

At the Habitation section of the station, Clark Johansson, one of the slaughter's survivors, heard the Stalker, and before it could get to him, he decided to commit suicide with his .357 Revolver. When he placed the gun on his chin, he gave up and decided to shoot anything that came close, but mistakenly shot and seemingly killed Dion Ross, a Colonial Marshal who was searching for survivors.

This caused Clark to break down after having killed another human. After retrieving Ross' M392 DMR, Clark prepared to enter an elevator, but he was stumbled by Dion, who revealed he survived the shot. As he asked for help, the Stalker appeared behind the Colonial Marshal. Without any more weapons, Ross pledged Clark to not leave him alone with the xenomorph, but Clark, panicking, entered the elevator and left the police officer behind, who was killed by the Stalker.

Arrival of the Torrens
Five days later, Diane Verlaine and her crew aboard the commercial freighter Torrens boarded Sevastopol Station in search of the flight recorder of the Nostromo. In the confusion, Amanda Ripley-McClaren was separated from the rest of the crew and became stranded on the space station.

The Stalker encountered Amanda as she traveled alongside the scavenger Axel Fielding, where the xenomorph impaled the man in the chest with its pail, pulling him to one of the station's many air ducts. For the following hours, Ripley was able to escape the Stalker until she found Dr. Clive Kuhlman, who was hiding in the San Cristobal Medical Facility. There, the doctor asked Ripley to find a missing information card from the body of his late assistant, Dr. Akira Morley. After she retrieved it and went back to Kuhlman, he returned to gather supplies, only to open it and find the Stalker. Before he could react, he was taken by the Stalker to the darkness of the ship while Ripley watched in horror.

Her next step was wandering through San Cristobal, avoiding many armed colonist survivors, in an attempt to find the code for a locked door. When she eventually found it, the Stalker dropped from the vents it was hiding, attacking the survivors, and killed them all. Before it could take Ripley, she unlocked the door and escaped once again. Afterwards, she found herself in an atrium, where the Stalker dropped down from a shaft, causing her to drop and crawl backwards to escape it. As the creature prepared to give her the final blow, the room's lights were switched and several timers were revealed, counting, leading to several explosions, which knocked Amanda unconscious and prompted the xenomorph to escape.

Awoken by Seegson Working Joe synthetics, she escaped them once she discovered they have been rampant ever since they have been deactivated and mysteriously turned on. She then found herself running from both the Working Joes and the Stalker, which destroyed as many synthetics as it could along the way. Despite finding two survivors, Francis Martinez and Andre Peterson, Amanda had to watch as Peterson was slaughtered by the Stalker who emerged from the shadows, while Francis was taken, nearly succeeding in taking her alongside him. After she escaped the area through an elevator, Amanda arrived at the fluid plant of the synthetics, witnessing the Stalker attacking a lone survivor, grabbing and dragging her to the depths of the area.

Death
Later, Amanda met Marshal William Waits and Deputy Ricardo Cristóbal, who argued with Samuels aboard how the creature entered the station, believing it to be a new, not yet found, Covenant species, where he revealed he had set up the explosives. The four of them joined together and devised a plan to trap the Stalker in the Gemini Exoplanet Solutions module and send it to space to its death. Their plan was a success, but the module ejected with both Ripley and the Stalker inside it. Before the alien killed her, she gained the upper hand and escaped from it through the airlock, while the Stalker was killed as the module fell and burned in Asimov's atmosphere.