Kumori Okami
Black Swordsman
heheheh, I can't top any of these, but I suppose I should share this one...
A few years back, me and my friend Matthew were using my newly acquired cell-phone to call random local numbers and come up with some kinda stupid shit to prank them with. So we call one house and this old lady picks up, right? Well, Matthew decides to (for the Gods know what reason) impersonate Fez from That 70's Show. And he was doing really well. He started asking her all these things about if she would buy him some chocolate and whether or not she had a hot daughter and all of this crazy stuff that you'd never expect anyone to come up with off the top of their head, right? So the old lady starts getting flustered and stuttering a lot, trying to keep up with his questions. So, in an effort to try and help her out, I did what any idiot would do... The classic Kelso impersonation while yelling at "Fez" not to make prank phone calls or someone might have him deported, and then hit the "end" button on my phone. We never thought about it again until a few days later...
Well, a few days passed and we had forgotten it, until I had gotten a new voicemail on my phone from the lady. Apparently she had caller ID and was going to turn in my immigrant friend if he didn't call and apologize to her.
So I had my girlfriend call the lady, insisting that she had no clue what was being said, but that phone was hers (she actually did record my voicemail message) and there was no way anyone would be able to prank call from it without her knowledge, then accused the lady of prank calling HER instead...
It really was kinda cruel, in retrospect, but I'd set it all up to do the same thing again in a heartbeat.