The Xenomorphs had descended on Outworld long ago, but the dormant eggs they left behind were only recently found. The leader of the Tarkatan patrol had picked up one of the leathery orbs, only to have it burst open and its occupant latch itself to his face. Later, after the "facehugger" had fallen off, the Alien progeny burst from the unfortunate Tarkatan's chest, bearing characteristics of both Xenomorph and host. It eluded the rest of the Tarkatan soldiers and eventually killed them. The creature now roams Outworld, looking for more hosts. Its amazing strength and animal fury make Alien almost unstoppable.
The Alien tore through Shinnok's flesh, reducing him to a bloody pulp. The creature then returned to its nest in Outworld. It continued to venture forth looking for suitable hosts for use in establishing a new hive. The Alien found more than a few intriguing species and dragged them back to its lair. Once a queen had been spawned, the Alien's new hive multiplied quickly and spread unchecked throughout the realm. Emperor Kotal Kahn attempted to save Outworld in a desperate final attack on the Aliens' main nesting ground. The attack failed. Outworld belonged to the Aliens.