The Trojan Horse
The episode revolves around the Trojan Horse, a large and hollow construction created to allow Greek soldiers hidden inside to enter Troy. Once inside and the residents asleep, the soldiers emerged and opened the gates, allowing the rest of the Greek Army into the city. Whether the strategem was actually employed as a matter of some debate, but the term has passed into common usage as a reference for any tactic that involves convincing an opponent to grant access under false pretenses. Some computer malware, such as BackOrifice, operates on this principle: the user installs a worthwhile program and secretly gets a program that grants a malicious outsider access.