Computer worm. Computer artwork of a worm emerging from a computer screen. This could be used to represent malicious computer programs known as worms. These programs are self- propagating viruses. Once they are activated, they often disrupt computer systems and spread by email or through networks to other computers. The replication and spread of worms can cause disruption to whole networks through sheer traffic generated and wasteful use of system resources. Notable examples of internet worms in the past have included: Mydoom, Love Bug, and Code Red.