High Quality Content by WIKIPEDIA articles! ShapeShifter is an Application Enhancer (APE) plugin for Mac OS X developed by Unsanity that allows the user to make system-wide modifications to the appearance of the operating system`s graphical interface by applying GUI skins through “injection” into running code and without modifying system files, very much like Kaleidoscope or WindowBlinds. It uses GUIKit files (called “themes”) which can contain interface elements, desktop backgrounds and icons. GUIKit files are most often edited using a program called ThemePark.