iFool

iFool app is designed to trick, spook and fool your friends, but they're unlike any other trick apps you've seen.

iFool makes use of your own device's screenshots and provides an elaborate mechanism to customize how a trick behaves and what events make it "fire." We've included a large and expandable library of images, sounds and preconfigured tricks from popping popcorn or leaving fingerprints to playing low-battery smoke detector chirps and alarms. You can even expand iFool with add-on packs. Outrageous help screens throughout the app will teach you how to get the most out of iFool.

Note: This is an iOS application.
While the software is classified as free, it offers in-App Purchases.