Pre-rework Akali
It was pretty stupid. In lane, it was pretty easy to play against her, until she got gunblade/ult. The only counter-play to Akali was to delay her getting gunblade long enough that she wouldn't have any damage. If she got the item, it didn't matter how ahead you were in lane, she would kill you. Then she would roam bot and get a double kill. And that, would be the game. I realize that Akali was pretty heavily nerfed by her rework, but her previous iteration wasn't fun to play against.