The Hammerpedes are very similar to real-life worms, but they are much larger. They were pale in color and had serpent-like bodies up to 4 feet long. Their crests are very similar to those possessed by cobras. These crests could be folded in and out around the creature's "head". They possessed incredible strength, able to break bones rather easily as was demonstrated when Fifield attempted to remove one from Milburn's forearm. They also possessed acidic blood as well as the ability to rapidly regenerate severed parts in a matter of seconds as shown when Fifield attempted to decapitate one, only to have its head quickly regenerate.
When the Prometheus arrived on LV-223, the crew, led by Dr. Shaw and Holloway discovered an Engineer temple, which they explored. They found a large room with a huge stone head inside and the room was dotted with urns. When the crew entered the room the urns started leaking black goo, and the crew left so as to not disturb the place. Millburn and Fifield, two members of the crew, got lost and managed to reach the urn room, where they saw that the urns had leaked much more goo. They discovered two Hammerpedes (mutated indigenous worms).
One of them rose and scared Fifield but Millburn looked upon it, fascinated. The creature attacked him, constricting his arm. Fifield tried to help Millburn, but only succeeds in breaking his arm. Then, Fifield cuts off the Hammerpede's head, revealing its acidic blood, which sprayed on Fifield. The Hammerpede then regrew its head, showing its regenerative abilities. It then enters Millburn's suit through the a hole made when his arm broke; it then enters his mouth, slowly killing him. Its acid blood melted Fifield's helmet, and Fifield fell into the goo, which would later begin to transform him into a grotesque mutant. Later when the rest of the crew goes to save the two members, they discovered the Hammerpede exiting from a dead Millburn, escaping. What happened to the two Hammerpedes later is unknown.