Spike was a Rottweiler who resided in the correctional unit on Fiorina 161 and was the canine companion of inmate Thomas Murphy. He was impregnated by a facehugger after it had emerged from the wreckage of one of the Sulaco's EEVs. Spike later died during the "the Dragon's" birth.
After the EEV that brought Ellen Ripley to Fiorina 161 is recovered, Spike barked at a Facehugger hiding in the wreckage, but is attacked and subdued. Murphy later found Spike in his room with his face lacerated from his struggle with the Xenomorph creature, mistakenly assuming one of the other inmates had attacked him out of cruelty. While the prisoners were attending a funeral service for the deceased Newt and Turk, the Runner that had been gestating inside Spike violently emerged, killing the dog before it escaped into the prison's ventilation shafts.
- The Assembly Cut of Alien3 removes Spike completely. Instead, the Runner gestates inside Babe, one of the prison's oxen (which are never seen in the theatrical version). Spike is also absent from the novelization of the film, which follows the Assembly Cut's plot as it was written before the film was altered to the theatrical version.
- In the comic book adaptation of Alien 3, Spike is known as "Sparky."
- In the comic, Spike's belly was half the size of []'s belly. But in the movie, Spike's belly was thin.