Alien: Covenant introduced the Neomorph, a terrifying, albino take on the classic monster, but where did this creature come from and how is it different from the original Xenomorph? The filmmakers behind the original Alien had a hard time coming up with a unique design for the creature until screenwriter Dan O'Bannon introduced director Ridley Scott to the artwork of H.R. Giger. Scott was instantly taken with Giger's disturbing imagery, with the title beast based off his painting Necronom IV.
When Ridley Scott returned to the franchise with 2012's Prometheus, he wanted to avoid bringing the original creature back. He felt decades of sequels and overexposure had rendered the beast harmless, so the movie became more of a spinoff than a true sequel. While Alien: Covenant started life as Prometheus 2, fan complaints about the lack of the Xenomorph led the studio to insist the creature return. This is why Covenant became something of a fusion between Prometheus and Alien.
Alien: Covenant also introduced a new monster dubbed the Neomorph. The notion of an albino creature first appeared in the original draft of James Cameron's Aliens, where white drones were in charge of cocooning victims in the hive; this concept was ultimately dropped. While the Neomorph's share similarities with the Xenomorph, they're also quite different.
Like the original creature, the Neomorph has a complex life cycle. They are found on Planet 4 by the Covenant's crew, where the local flora and fauna has been infected by the Engineer's black goo, following villainous android David 8 (Michael Fassbender) unleashing the weapon on the planet's previous inhabitants. This caused the growth of the Neomorph egg sack, a seemingly benign fungal growth that unleashes spores if disturbed. These almost invisible spores then target and enter an available host. This leads to the rapid development and growth of a Bloodbuster sack, which quickly erupts and kills the host after a few hours.
These newborns rapidly form into Neomorphs, which like the Xenomorph is eyeless and incredibly violent. Alien: Covenant shows they lack the intelligence of the title monster, however, and mindlessly attack any available target. They lack the iconic inner jaw of the Xenomorph and instead have detachable mouths like a Goblin Shark and are easier to kill, with some well-aimed rifle fire enough to put them down. Since the two Neomorph's found in Covenant don't last long, it's unknown if they share other Xenomorph characteristics like producing eggs or cocooning victims.
The design for the Neomorph itself came from the first draft of Prometheus when it was known as Alien: Engineers. Engineers was a direct Alien prequel and featured eggs, facehuggers and a new take on the original creature called the Beluga-Xenomorph, a white creature that could squeeze itself through tight spaces. The notion of a xenovirus is also borrowed from author William Gibson's unused draft of Alien III, where an airborne contagion can rewrite the DNA of victims and create human/xeno hybrids. Like the Neomorph, this virus also came from a fungal, egg-like sack.
The Neomorphs also form part of David 8's experiments on Planet 4 with the black goo, in his attempt to build his "perfect" creation. Alien: Covenant somewhat controversially suggests it was actually David who created the Xenomorph, though its possible he just refined an Engineer design. The Neomorph proved to be a creepy new addition to the Alien life cycle and proved H.R. Giger's original design is endlessly flexible.