Human-Form Replicators

Replicator

A basic Replicator "bug"
Stargate SG-1 race
Attributes
Kind	Mechanical race
First appearance	"Nemesis" (2000)

In the military science fiction series Stargate SG-1, the Replicators are antagonistic self-replicating machines that are driven to replicate by consuming both alloys and technologies of the nearest most advanced civilization and constructing themselves and their progeny accordingly. They were first mentioned indirectly in the season 3 episode "Fair Game", and first seen onscreen in "Nemesis". In the show, the Replicators are primarily the enemies of the Asgard race, however, they act like a plague against all life thus, in the series, Earth must also contend with them on several occasions. The Asurans in the spin-off series Stargate Atlantis might be related to those in Stargate SG-1 as they are essentially human-form "Replicators".

The Replicators first appear in the season 3 finale "Nemesis", following hints by Thor in "Fair Game" about an enemy worse than the Goa'uld in their home galaxy of Ida. SG-1 faces off against the Replicators who have infested Thor's mothership, the Beliskner, to prevent them from invading Earth. They destroy the deceleration drive on the Beliskner, causing it to burn up in Earth's atmosphere. In the following episode "Small Victories", a single surviving Replicator from the Beliskner infests a Russian submarine before being neutralized. At the same time, Samantha Carter helps Thor avert an imminent Replicator invasion of the Asgard homeworld, Halla. In the season 5 premiere "Enemies", SG-1 encounters the Replicators after being thrown to another galaxy by a supernova. The Replicators take over their Goa'uld mothership and head for the Milky Way; to prevent them from reaching their destination, SG-1 sabotages the mothership's engines so that it crashes into the planet Delmak upon exiting hyperspace.