the smoking worm dances over your screen to the music
You can download a prebuilt .jar file from here. If You have Java installed on your machine, you can run it by double clicking it. For the worm to react to the music that is currently playing, you have to ensure that system monitor is set as the input device for recording.
Warning The program opens in fullscreen mode and doesn't have any stop button. To exit try hitting ESC, ALT+F4, CRTL+Q, ...
This program is written in Processing 3 so you need to have that installed if you want to play around with the code. You will also need Minim. Download the code from this page, open it in the Processing IDE and click 'run'.
If you want to build a standalone .jar by yourself, open the code in the Processing IDE and click File > Export Application. This will create a folder application._ where _ is your operating system. It contains a folder lib. Inside that folder, run build.sh (make sure to chmod +x build.sh first). This will create audioScreensaver_standalone.jar which is the desired .jar. It can be run by typing java -jar audioScreensaver_standalone.jar in a terminal or by double clicking.
This software comes with no warranty.