When you install the app, you'll only have 30 seconds to play the joke. If you want more time, then you need to watch ads, install other apps, or buy time directly through the app. As long as you have time, you can call any number you want and talk with a disguised voice. You can even add funny sound effects like farts, barking, or gunshots.
FunCall is prank phone call app that could make for a really fun time. All you need, of course, is a worthy victim to play the prank on.
Requires Android 4.0.3 or higher
The demo version only lets you convert 25 emails.