The Hammerpede is the result of indigenous worms of LV-223 being exposed to Chemical A0-3959X.91 – 15. Whether they can be formed from other species of worm on other planets is unknown.
The Hammerpede has pale, white-grey skin with a somewhat translucent appearance, attributes that resemble those of a Neomorph. Like the indigenous worms they mutated from, Hammerpedes have serpent-like bodies but can grow up to 4 feet long. Their ‘crests’ are reminiscent of the hoods possessed by cobras. These ‘crests’ can be folded in and out around the creature’s mouth. They possess incredible strength, able to break bones rather easily, which was demonstrated when Fifield attempted to remove one from Millburn’s forearm. They also possess acidic blood and the ability to rapidly regenerate severed parts in a matter of seconds, which was seen when Fifield attempted to decapitate one, only to have its head quickly regenerate.
In the Movie Prometheus
When the USCSS Prometheus arrived on LV-223, the crew, led by Dr. Elizabeth Shawand Charlie Holloway, discovered a temple, which they explored. When they disturbed a room containing ampules of Chemical A0-3959X.91 – 15, the chemical began to leak out of the urns onto the floor, infecting several worms which mutated into Hammerpedes.
Millburn and Fifield, two members of the crew, got lost and managed to reach the same urn room, where they discovered two Hammerpedes. One of them rose and scared Fifield but Millburn looked upon it, fascinated. Millburn appeared to try and touch the creature, but it flared its ‘crests’ and attacked him, constricting Millburn’s arm. Fifield tried to help Millburn, but his touching it only made the Hammerpede constrict tighter, which resulted in it breaking Millburn’s arm. In a further attempt to save Millburn, Fifield cut off the Hammerpede’s head, causing its acidic blood to spray on Fifield’s helmet faceplate, which melted it. The Hammerpede then regrew its head, showing its regenerative abilities and slipped into Millburn’s suit through a hole made by his protruding bone, entering his mouth and subduing him.
Meanwhile, Fifield fell into the A0-3959X.91 – 15 on the floor, which would later begin to transform him into a grotesque mutant. When the rest of the crew went to save the two members the next day, they discovered Millburn’s body, and a Hammerpede jumped out of his mouth and back into the A0-3959X.91 – 15.