Replicators

The Replicators are a race built from nano-technology. When they first appeared in Stargate SG-1 they took the form of a spider or beetle type insect, gaining them the nickname of Techno Bugs. Later in the series, and then in Stargate Atlantis they also took the form of humanoids. The nanites that comprise the Replicators commonly take the form of blocks which can fit together to make different shapes.