Users of Mac OS X in the 2000s might remember the shareware company Unsanity and their Application Enhancer and "haxies" that modified system behaviors, like MightyMouse for custom cursors or ShapeShifter for UI themes.

Apple eventually waged war against code injection and by OS X 10.7, Unsanity's products were made obsolete.

Former Unsanity developer Rosyna Keller has recently revived two of their products for modern macOS: Xounds adds UI sound effects like OS 9's Platinum, and FruitMenu permits customization of the Apple menu.