Typhoid Mary

Typhoid Mary is a deceptive program. It appears to attack as a Killer II, and can function as such. However, this is a cover to attack the Netrunner's deck, and when the "Killer" is attacked by the 'rurnner, it always "crashes." If fact, the program disappears into the cyberdeck's CPU (successful roll vs cyberdeck datawall), where it operates for three Net rounds, deleting a file each round as Viral 15. At the end of three rounds, it derezzes, leaving the 'runner with missing files and/or utilities. Action can only be taken against the program if the Netrunner is aware of (or suspects) its presence. GateMaster will stop its actions, but it has to be activated by the 'runner.

Source

• Chromebook Volume 3, pg.77