Final answer:
A worm is a type of malware that can replicate itself to cause harm to a computer system, including consuming bandwidth, deleting files, and enabling remote control.
Step-by-step explanation:
The type of program that replicates itself once inside a computer system causing a variety of problems is a worm. Worms are a form of malware that can spread without any human interaction, often exploiting vulnerabilities in software or operating systems. Unlike viruses, which require the spreading of an infected host file, worms are standalone software and do not require a host program or human help to propagate. They can cause harm by consuming bandwidth, deleting files, sending spam, and allowing remote control by attackers.