Downloading Plash 2.15 for Mac from the developer's website was possible when we last checked. We cannot confirm if there is a free download of this app available.
Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. The actual developer of this free software for Mac is Sindre Sorhus. Plash for Mac relates to Theming Tools.
From the developer:
Plash can make any website your desktop wallpaper. This enables you to have a highly dynamic desktop wallpaper. You could display your favorite news site, Facebook feed, or a random beautiful scenery photo. The use-cases are limitless. You could even set an animated GIF as wallpaper.
You may want to check out more Mac applications, such as Desktop Wallpaper Construction Kit, Add Movie Wallpaper HD or uDesktop HD Lite, which might be similar to Plash.