An Easter egg is an intentional inside joke, a hidden message, or a secret feature of an interactive work (often, a computer program, video game or DVD menu screen). The name is used to evoke the idea of a traditional Easter egg hunt. The term is created to the discovery of a hidden message in the Atari video game Adventure, which led Atari to encourage further hidden messages in later games, treating them as Easter eggs for players to find.
While not the first use of an hidden message in a work, the origin of the term "Easter egg" to describe these originated from the 1979 video game, Adventure for the Atari 2600. The game was programmed by Atari employee Warren Robinett. At the time, the video game production companies like Atari feared that by crediting programmers with the games they created, competitors would attempt to steal away their employees. Robinett, who had some issues with his supervisor over this and other issues at the time, secretly inserted the message "Created by Warren Robinett", which would only be triggered if the player moved their avatar over a single pixel (the "Gray Dot") in a certain part of the game. Robinett had not told anyone at Atari about this by the time he left the company. Shortly after his departure, the Gray Dot and his message was discovered by a player, who wrote their discovery into Atari. Atari's management initially wanted to reprogram and rerelease the game to remove the message, but this was a costly effort. Steve Wright, the director of software development of the Atari Consumer Division at the time, suggested that they keep the message and encourage future games to include such messages, describing these as Easter eggs for consumers to find, and thus coining the term.
In computer software, Easter eggs are secret responses that occur as a result of an undocumented set of commands. The results can vary from a simple printed message or image, to a page of programmer credits or a small video game hidden inside an otherwise serious piece of software. Video game cheat codes are a specific type of Easter egg, in which entering a secret command will unlock special powers or new levels for the player. The first Easter egg to be found in a video game is the 1978 Adventure, which includes a secret room only accessible through a complicated series of gameplay steps. The secret room displays the message "Created by Warren Robinett". Because Atari did not publicly credit game designers, Robinett inserted the message after the game's completion partially in an attempt to gain some recognition for his work. The egg was discovered by a 15-year-old player in 1980, who wrote to Atari to tell them that he had found "something strange" in the game.
In the TOPS-10 operating system (for the DEC PDP-10 computer), the
make command is used to invoke the TECO editor to create a file; if given the file name argument
love, so that the command is
make love, it will pause and respond
not war? before creating the file. This same behavior occurred on the RSTS/E operating system, where TECO will provide this response. Other Unix operating systems respond to "
why" with "
why not" (a reference to The Prisoner in Berkeley Unix 1977).
Some versions of the DEC OpenVMS operating system have concealed exit status codes including a reference to the Monty Python Dirty Hungarian Phrasebook skit "
exit %xb70" returns the message "%SYSTEM-W-FISH, my hovercraft is full of eels" while "
exit %x34b4" returns a reference to an early Internet meme "%SYSTEM-F-GAMEOVER, All your base are belong to us".
Many personal computers have much more elaborate eggs hidden in ROM, including lists of the developers' names, political exhortations, snatches of music, or images of the entire development team. Easter eggs in the 1997 version of Microsoft Office include a hidden flight simulator in Microsoft Excel and a pinball game in Microsoft Word.
An Easter egg is found on all Microsoft Windows operating systems before XP. In the 3D Text screen saver, entering the text "volcano" will display the names of all the volcanoes in the United States. Microsoft removed this Easter egg in XP but added others. Microsoft Excel 95 contained a hidden Doom-like action game called The Hall of Tortured Souls.
The Google search engine famously contains many Easter eggs, given to the user in response to certain search queries. For example, Google Maps once responded to a request for directions from New York City to Tokyo by telling the user to kayak across the Pacific Ocean.
Steve Jobs banned Easter eggs from Apple products upon his return to the company. The first Easter egg to appear after his death was in a 2012 update to the Mac App Store for OS X Mountain Lion, in which downloaded apps were temporarily timestamped as "January 24, 1984", the date of the sales launch of the original Macintosh.
While computer-related Easter eggs are often found in software, occasionally they exist in hardware or firmware of certain devices. On some home computers, the BIOS ROM contains Easter eggs. Notable examples include some errant 1993 AMI BIOS that on November 13, 1993, proceeded to play "Happy Birthday" via the PC speaker over and over again instead of booting, and several early Apple Macintosh models which had pictures of the development team in the ROM (accessible by pressing the programmer's switch and jumping to a specific memory address, or other equally obscure means). These Mac easter eggs were well-publicized in the Macintosh press at the time, along with the means to access them, and later serendipitously recovered by NYC Resistor team, a hacker collective, through elaborate reverse engineering,. Similarly, the Radio Shack Color Computer 3's ROM contains code which displays the likenesses of three Microware developers on a Ctrl+Alt+Reset keypress sequence—a hard reset which discards any information currently in RAM.
Several oscilloscopes contain Easter eggs. One example is the HP 54600B, known to have a Tetris clone (and even to save high scores), whereas the HP 54622D contains an implementation of the Asteroids game named Rocks. Another is the Tektronix 1755A Vector and Waveform Monitor which displays swimming fish when Remote>Software version is selected on the CONFIG menu.
In the second and third hardware revision of the Minolta Dynax/Maxxum/Alpha 9 SLR camera, including all SSM/ADI upgraded cameras, an undocumented button sequence which is impossible to press by accident, can be utilized to reconfigure the camera to behave like the Dynax/Maxxum/Alpha 9Ti and subsequently invoke support for the limited model's extra functions also in the black model.
The Commodore Amiga models 500, 600, and 1200 each feature Easter eggs, in the form of titles of songs by The B-52's as white printing on the motherboards. The 500 says "B52/Rock Lobster", the 600 says "June Bug", and the 1200 says "Channel Z". The Amiga OS software contains hidden messages.
Many integrated circuit (chip) designers have included hidden graphic elements termed chip art, including images, phrases, developer initials, logos, and so on. This artwork, like the rest of the chip, is reproduced in each copy by lithography and etching. These are visible only when the chip package is opened and examined under magnification, so they are, in a sense, more of an inside joke than most of the Easter eggs included in software. The 1984 CVAX microchip implementation of the MicroVAX CPU contained in its etchings the Russian phrase in the Cyrillic alphabet "VAX: When you care enough to steal the very best", placed there because, "knowing that some CVAX's would end up in the USSR, the team wanted the Russians to know that we were thinking of them".
Easter eggs are found on film DVDs and Blu-rays, often as deleted scenes or bonus special features. Klinger states that their presence is "another signifier of artistry in the world of DVD supplements." According to Berardinelli and Ebert, most DVDs do not contain them, and most examples are "inconsequential", but a very few, such as one found on the Memento DVD release, are "worth the effort to seek out".
The TV series Doctor Who has an episode using Easter eggs as a major part of the plot; the episode in question even has an Easter egg on the chapter selection for that episode on the disc release, showing the full in-episode Easter egg.
Unlike DVDs and computer games, broadcast radio and television programmes contain no executable code. Easter eggs may still appear in the content itself, such as a hidden Mickey Mouse in a Disney film or a real telephone number instead of a 555 fictitious telephone number. One 2014 Super Bowl advertisement was leaked on-line in which a lady gives a man a real telephone number which the advertiser had hidden as a marketing ploy; the first caller to the number received a pair of tickets to the game. The 1980s animated series She-Ra: Princess of Power featured a character, Loo-Kee, who typically was hidden in a single screenshot within an episode, marking his only appearance in that episode. After the end of the episode, the screenshot would be shown again and the character would challenge viewers to locate him, before revealing his hiding place.
Robinett's addition of his name to Adventure (1979) is recognized as the first well-known Easter egg, as well as the origin of the term. However, there may be Easter eggs that predate this, particularly in the realm of arcade games. In 2004, an earlier Easter egg was found in Video Whizball, a 1978 game for the Fairchild Channel F system, displaying programmer Bradley Reid-Selth's surname. According to research by Ed Fries, the first known Easter egg in arcade games came from Starship 1, programmed by Ron Milner and released in 1977, although it's existence wasn't published until 2017. By triggering the cabinet's controls in the right order, the player could get the message "Hi Ron!" displayed to them on the screen.
Since Adventure, there has been a long history of video game developers including Easter eggs in their games. Sometimes the intent was to communicate with the player; sometimes it was a way of getting even with management for a slight. For example, Robinett's first egg was included because he wanted credit for programming the game, which was not customarily included at the time. Easter eggs in video games have taken a variety of forms, from purely ornamental screens (like Robinett's) to aesthetic enhancements that change some element of the game during play, such as the Easter egg included in the original Age of Empires game that changes catapult projectiles from stones to cows.
More elaborate Easter eggs include secret levels and developer's rooms, fully functional yet hidden areas of the game. Developer's rooms often include inside jokes from the fandom or development team, and differ from a debug room in that they are specifically intended for the player to find. Some games even include hidden sub-games as Easter eggs. In 1993's acclaimed LucasArts video game Day of the Tentacle, the original game Maniac Mansion from 1987 can be played in its full version by using a home computer in one character's room.
Security author Michel E. Kabay discussed security concerns in 2000, saying that software quality assurance requires that all code be tested, but it is not known if Easter eggs are tested. He said that because they tend to be held as programming secrets from the rest of the product testing process, a "logic bomb" could also bypass testing. Kabay asserts that this undermined the Trusted Computing Base, a paradigm of trustworthy hardware and software, in place since the 1980s, and is of concern wherever personal or confidential information is stored, which may then be vulnerable to damage or manipulation. Microsoft created some of the largest and most elaborate Easter eggs, such as those in Microsoft Office. In 2005, Larry Osterman of Microsoft acknowledged Microsoft Easter eggs, and his involvement in development of one, but described them as "irresponsible", and wrote that the company's Operating System division "has a 'no Easter Eggs' policy" as part of its Trustworthy Computing initiative.
Douglas W. Jones said in 2006, "some Easter eggs may be intentional tools used to detect illegal copying, others are clearly examples of unauthorized functionality that has slipped through the quality-control tests at the vendor". While hidden Easter eggs themselves are harmless, it may be possible for malware to be hidden in similar ways in voting machines or other computers.
Netscape Navigator contributor Jamie Zawinski stated in an interview in 1998 that harmless Easter eggs impose a negligible burden on shipped software, and serve the important purpose of helping productivity, by keeping programmers happy.
Microsoft’s developers hid multiple Easter Eggs in Word 95/97/2000.