The aliens were Humanoid in shape but appeared far differently with a hard reddish exo-skeleton. Their heads were covered in a helmet shaped structure with their mouth containing a mandible shaped structure which can produce a deep noise that was capable of being projected for others of their kind to hear, but was not understood by human ears.
They showed no fear of dying and were quite willing to die rather than face capture. Furthermore, they made use of holographic technology to disguise themselves, and seemed capable of interacting with humans through this means but not in their natural form. As evidenced by lethal gunshot wounds, their blood was purple in colour and gunshots were capable of killing them. (SG1: "Foothold")
The Stragoth managed to infiltrate Stargate Command by impersonating SG-6 which they accomplished by using their Mimetic imaging devices which allowed them to appear Human. Where upon they installed a Scanning device for further operations. However, the process was not successful on everyone. Teal'c and Major Samantha Carter were incapable of being impersonated due to Teal'c and his Goa'uld, and Carter having Naquadah in her blood due to Jolinar of Malkshur, which prevented their duplication.
This allowed the two to escape though Teal'c was captured but not before allowing Carter to successfully escape from Cheyenne Mountain. From there, she called for the aid of Colonel Harold Maybourne to stop the Foothold situation but the NID Colonel did not believe her. While escorting her back on a plane carrying imposters of Colonel Jack O'Neill and Dr. Daniel Jackson, the noise from the aircraft began to interfere with the mimic devices which revealed their true form. The two Stragoth were killed as a result and showed proof of alien infiltration.
At the SGC, the death of the imposters allowed for O'Neill to awaken from the alien technology after which he freed himself and others who had their imposters killed. Carter herself managed to infiltrate the installation and discover a means of interfering with the mimic devices. As an NID Strike Force under Maybourne's direct command stormed the base, the aliens began an evacuvation procedure through the Stargate. However, members of the Stargate Program managed to shut down the gate before all the aliens managed to escape. Trapped, the leader of the Stragoth activated the self-destruct with his remaining forces and they died in the resulting explosion in the gate room. What happened to the seven Stragoth that got away is currently unknown. In order to prevent future such incursions by these aliens, all travellers were subjected to a sonic field to disrupt the mimic technology. (SG1: "Foothold")
It was later established that the foothold situation created by the Stragoth at Stargate Command was considered such a disastrous security breach that the incident was struck from all official records. (SG1: "Smoke and Mirrors")
Behind the ScenesEdit
The unpublished Fallout: Stargate Season Three sourcebook for the Stargate SG-1 Roleplaying Game developed by Alderac Entertainment Group named the "mimetic aliens" as the Stragoth, which is used as their name in this article as they have been given no name since then.
Some fans speculate that the Stragoth may actually be from another galaxy due to a statement by one of the infiltrators who comments that the Goa'uld are the 'dominant race in this galaxy'. Stargate SG-1: The DVD Collection 6 gives their home planet as P3X-118, however this is only confirmed as the planet SG-6 encountered them on.