It's pretty laggy, but if you can get this project to load properly, there should be a worm that slowly changes color. I finished this a while ago, but I never shared it... This is a sprite that uses cloning for the tail. It works with the arrow keys and WASD. The head changes color, making the rest of the body look like a wave of changing colors. The worm can move backwards, but it was really weird, so I removed it. The blocks are still there if you want to reconnect them, though.
Merry Christmas! I wouldn't recommend fullscreen mode...