Khalek was a Human-Goa'uld Hybrid created by Anubis on P3X-584. Anubis reconstructed his own DNA and combined it with Human DNA and accelerated his evolutionary development using a DNA resequencer. Khalek had the genetic memory of Anubis, along with Anubis' sociopathic and homicidal tendencies, and referred to Anubis as his "father". He also possessed various powers of Near ascension such as psychokinesis, telekinesis, telepathy, rapid healing ability, and was well on his mental development to natural Ascension.
After SG-1 took him out of stasis and brought him back to Stargate Command for a check-up, he initially claimed to be a victim of Anubis' experiments, but Dr. Daniel Jackson discovered the truth. Jackson warned that the risks he presented were too great to allow his continued survival, but Richard Woolsey advocated studying him, reasoning that analysis of Khalek might both help them learn more about their own future evolution and devise a means of stopping someone with Khalek's powers in a field combat situation, a danger made more real due to the arrival of the Priors of the Ori in our galaxy. During subsequent conversations between him and Jackson, Khalek often taunted Jackson with reference to the confrontation between Jackson and Anubis when Daniel was Ascended (SG1: "Full Circle"), as well as constant references to his own desire to kill.
Jackson proved to be right about the danger presented by Khalek, and Khalek killed two guards while trying to escape. He gated to P3X-584, but the Call forwarding device that had initially prevented SG-1 dialling that address had been reprogrammed to send him back to Stargate Command. Before he could overcome his surprise at this unexpected turn of events, Lt. Colonel Cameron Mitchell and Dr. Jackson shot and killed Khalek while he was distracted. (SG1: "Prototype")
- Before the episode aired, a draft of the original script was said on Gateworld to reveal that Anubis's purposes for Khalek was to make Khalek part of an army of warriors called the "Mashur", which was derived from the Goa'uld word "Mashur-nat" meaning "Mutation". Anubis's plans for this army was to train them to ascend and do battle with the Ascended Ancients on their plane of existence and ultimately destroy them. However, this was cut from the episode.