In the first-season The X-Files episode "Ghost in the Machine", Eurisko is the name of a fictional software company responsible for the episode's "monster of the week", facilities management software known as "Central Operating System", or "COS". COS (described in the episode as an "adaptive network") is shown to be capable of learning when its designer arrives at Eurisko headquarters and is surprised to find that COS has given itself the ability to speak. The designer is forced to create a virus to destroy COS after COS commits a series of murders in an apparent effort to prevent its own destruction.