Replicators are a civilization of self-replicating machines native to the Stargate universe.
The most basic level of Replicator is the block. Replicator Blocks are small objects about 2.5 centimeters long. On their own, individual blocks are incapable of acting, However when several of these blocks come in close proximity, they can use magnetic force to assemble themselves into various forms. A typical form is an insectoid shape ranging in size from a small dog to a large dog. Such a form is capable of movement, processing metal, and producing additional replicator blocks. Larger forms are capable of spaceflight at FTL speeds. Replicators are powered by an exotic particle, and power has so far never been an issue for them. Replicators also carry a corrosive spray capable of eating through metal; the properties of this are unknown although some have suspected it to be nanotechnologically based. Through unknown means, Replicators exhibit a rather high resistance to energy weapons, but they are still vulnerable to projectile weaponry, such as firearms.
Replicators are intelligent and work as a group mind. They are capable of using machinery, such as ships and computers, as well as enhancing their weapons systems, shields and propulsion. Replicators do not carry small arms, instead attacking enemy soldiers on the ground by clawing at them and using their corrosive spray. Replicators have two main strategies: using their small size to lay low while building up their numbers and engaging in ambush tactics, then swarming soldiers under vast numbers of spider forms.
Ultimately the Replicators have one primary drive, self-replication. Any Replicator insectoid form can process metals and produce additional blocks at a sufficient rate to create an another insectoid form in a matter of minutes. This Drive inevitably brings them into conflict with other sapient species, which they see as threats that hinder their ability to replicate, making them hostile to any other life form they encounter.
Replicators are one of the most hostile, powerful and dangerous factions in the Stargate universe. While a single basic Replicator spider form is not much of a threat by itself, it is capable of quickly generating several additional Replicators, which are further capable of expanding their numbers exponentially if enough raw materials are available. This gives the Replicators not only a colossal numerical advantage but also makes them extremely hard to contain and vanquish once and for all. A single space-capable Replicator form can generate a massive army of Replicators capable of galactic conquest in a matter of months. Combined with the ability to commandeer and upgrade warships, this makes even a single Replicator spider form a threat on a galactic scale.
Replicators of Note