Emma Emmerich's worm cluster was a program made up of several computer worms, each one designed to target a specific part of GW's AI system.
The worm cluster was programmed to mimic the data packets that comprised GW. Because of this, GW's scanning agents would be unable to detect the program, and thus could not trigger its antibody production system. The worm program could also penetrate GW's bit brain barrier until it reached its neural network. Once inside GW's neural net, the worm cluster would transform the surrounding neurons by turning them solid and thus make them incapable of resuming their duty as neural nets. After some time, the transformed neurons would perish after transformation, which would lead to the overall system being stripped of its power to define and comprehend data. In turn, this would then lead to language disorders and memory loss, and eventually the shutdown of functions, as the system would no longer be capable of maintaining itself. It was modeled after FOXDIE.
Emma Emmerich designed the worm cluster, on orders of the Patriots, as a safeguard in case GW fell into the wrong hands. The Patriots also secretly added in a program that would erase the identities of the Wisemen's Committee. The worm was uploaded into GW during the Big Shell Incident, though its progress was seemingly halted at 90% by an antibody agent. Despite this, following a slight delay, it eventually began to affect GW. Raiden discovered this when his supposed C.O., the Colonel, began to act in a strange manner and was revealed to be an AI construct of GW's. The worm then fully corrupted the GW system as well as everything connected to it, with Revolver Ocelot informing Solidus Snake of this just as the corrupted RAYs were starting to go haywire, also forcing the Arsenal Gear to surface. The worm's coding was later reverse-engineered by Philanthropy to locate the identities of the Wisemen's Committee in the programming, although they later discovered that the identities were duds.