I'm not usually a supporter of apps that don't have much of a purpose, especially the ones that fall under the "pranks" category. Now, I say "usually" because most of the time these apps are pretty stupid (I'm looking at you, iFarts) or not very prank-worthy.
Rarely, however, worthy apps do come out, and the recent Shavester is one of them - it caught my attention due to the freakout potential of turning your merry friends into something like Britney here, except not as happy, if only for just a few seconds.
The premise behind Shavester is very simple:
Step 1: Install the app and start it.