The hammerpedes are cobra-like creatures that were introduced in the film Prometheus. These extraterrestrial creatures are the result of indigenous worms being exposed and mutated by the A0-3959X.91-15 chemical. It is currently unknown if they could be produced on other planets.
Two hammerpedes were sighted when Milburn and Fifield were alone in the urn room of the abandoned ship. One approaches Milburn and Fifield, and it immediately unnerves Fifield. However, Milburn expressed curiosity for the strange creature, and attempted to reach out and touch it. The hammerpede then proceeded to flare its crest, and attack his arm. Fifield attempted to help his comrade by getting the wretched creature off his hand, but he only succeeds in breaking his arm. Fifield then cuts the hammerpede's head off only to discover that it could regenerate a new head. The creature then proceeds to go into Milburn's suit, and enters his mouth.
Milburn later fell into a pool of A0-3959X.91-15 and it slowly transformed him into a mutant. The crew of the USCSS Prometheus then discover his body, and a hammerpede escapes from his body.