Miscalculationator

This isn't your run-of-the-mill calculator! Besides just arithmetic'ing, it has two special modes that you can use to bewilder your more gullible friends.

The first mode will give completely wrong answers. The second mode provides a sarcastic comment instead of an answer. Oh, Miscalculationator, will you ever play nice? I hope not!

To enter or leave one of these stealth modes, just hit the 'times' or 'divide' buttons four times in a row ('times' puts you into 'sarcastic comment' mode, while 'divide' puts you in 'wrong answer' mode).

Put it in stealth mode when a friend needs a calculator! When he or she hands it back, take it out of stealth mode. Hilarity will ensue! Or your money back!

Check out the quick demo video to see this app in all its awesome glory.

Also, it's free! But I threw ads in there. A worthy trade-off, I'm sure you'll agree.