EDIT: February 12, 2010. Modified script and placed it in a new menu location (no other changes). Rather than calling it an "Animated" Plastic Wrap, it should, more appropriately be called, "Plastic Wrap All Layers". You can now find it under Filters > Light and Shadow > Plastic Wrap All Layers... Please delete your other script if you downloaded it before today.
This script quickly adds a "plastic wrap" effect on all layers in an image. The preview image above is just a plastic wrapped version of the lava animation preview here: [link]
The plastic wrap is a GIMP version of the PS filter and was created by newt and discussed here: [link] The script at that location works on a single layer; mine, all layers.
Download the zip file, open the zip file by double-clicking on it and copy/paste the script to your GIMP scripts folder (ie...C:\Program Files\GIMP-2.0\share\gimp\2.0\scripts). Refresh your scripts and you're ready to go. The script can be located under the Filters > Light and Shadow > Plastic Wrap All Layers... The lower number you use, the more plastic added.
Let me know if you have any trouble or need additional information.
[link]