Johnny Castaway is a screensaver

Screensaver

A screensaver is a type of computer program initially designed to prevent phosphor burn-in on CRT and plasma computer monitors by blanking the screen or filling it with moving images or patterns when the computer is not in use...

 released in 1993 by Sierra On-Line

Sierra Entertainment

Sierra Entertainment Inc. was an American video-game developer and publisher founded in 1979 as On-Line Systems by Ken and Roberta Williams...

/Dynamix

Dynamix

Dynamix, Inc. was an American developer of computer games from 1984 to 2001, best known for their flight simulator, Red Baron, the Front Page Sports series, Betrayal at Krondor, and their online multiplayer game, Tribes.-History:...

, and marketed under the Screen Antics brand.

The screensaver depicts a man stranded on a very small island with a single palm tree. It follows a story which is slowly revealed through time. It takes many days to catch on to the story. While Johnny eats, fishes, builds sand castles, and sleeps on a regular basis, there are a number of unusual events such as the island getting crushed by a ship that Johnny attracted, Johnny getting tied up, and a mermaid

Mermaid

A mermaid is a mythological aquatic creature with a female human head, arms, and torso and the tail of a fish. A male version of a mermaid is known as a "merman" and in general both males and females are known as "merfolk"...

 coming to the island.

"Johnny Castaway" also features holidays of the year such as Halloween

Halloween

Hallowe'en , also known as Halloween or All Hallows' Eve, is a yearly holiday observed around the world on October 31, the night before All Saints' Day...

, Christmas

Christmas

Christmas or Christmas Day is an annual holiday generally celebrated on December 25 by billions of people around the world. It is a Christian feast that commemorates the birth of Jesus Christ, liturgically closing the Advent season and initiating the season of Christmastide, which lasts twelve days...

, July 4th and others.