Blueballs (Also known as Virus.Win32.Blueballs) is a virus on Microsoft Windows. It is not as malicious as other viruses, as this virus' payload is cosmetic, and doesn't do or attempt to do anything to destroy the computer.
The virus only activates on January 1st. When run, blue balls start appearing on the monitor, multiplying rapidly. However, this is a merely cosmetic payload, and not much else happens, the user can still use the computer normally. While the payload covers the icons, the user can still click on the icons.
The payload also has a display error, as it looks like the virus was made for an 800x600 resolution, so if the virus is used on a computer with a higher resolution, the virus will appear in the upper left of the screen instead.
The payload can be stopped by simply reseting the computer, or terminating the program in task manager.