Fan fiction is an interesting thing. Fans of a series of movies, games, comics, or anything in general will write their own verisons of the story they love. Maybe they'll expanded upon something, put the characters in a different setting to see how they would be, rewrite the story a bit to put a new spin on it, or something else. It is sort of the like the Elseworlds comics that DC occasionally releases.
Now fan fiction is and can... be pretty bad or average. I've written it in the past and with exception of one story (Pokemon WaterBlue which is more of an alternative telling of the original Pokemon video games, but with a new evil team in it), I was really not that good looking back on it. However, I can safely say that I have never gotten to the point of some stories where they just... you know what? Seeing things for yourself explains it better or hearing it. Here are some of the very worst in fan fiction I think:
http://thatguywiththeglasses.com/bt/the-sage/fanfic-theatre/22486-cloud-mows-the-lawn2 Girls and One Cup has nothing on that story! Hope you didn't like Final Fantasy VII that much!
http://tvtropes.org/pmwiki/pmwiki.php/FanFic/AgonyInPinkFor your own sanity, I have decided not to post the story or a video of it. You'll thank me later!
http://tvtropes.org/pmwiki/pmwiki.php/FanFic/MyImmortalhttp://thatguywiththeglasses.com/bt/the-sage/fanfic-theatre/15170-ep012aMy Immortal is probably the most famous of all bad fan fiction in the world. It also has some so bad that it is good moments depending on how you view.
So now that I've shared (There's more, but I don't think you want to know anymore of the creepy and horrible fan fiction I've found), how about you guys? Have you run into any bad fan fiction you would like to share?