Easter eggs are
|“||[any] [h]idden functionality within an application program, which becomes activated when an undocumented, and often convoluted, set of commands and keystrokes are entered. Easter eggs are typically used to display the credits for the development team and are intended to be non-threatening.||”|
|“||messages, events, or effects hidden by game developers that are typically not encountered during regular game play, or require inside knowledge to catch, if they are. They often contain programmer signatures, homages to earlier titles, advertisements for upcoming games, or genre in-jokes.||”|
In videogames, issues occasionally arise when this content has not been reviewed or rated by the Entertainment Software Ratings Board (ESRB). This practice can result in games being recalled and/or ratings being changed as well as providing the basis for private lawsuits and federal investigations.