Just heard the boys on Podtoid from Destructoid make mention of this creepy little fan-fic: "Ben Drowned." Started reading it, and it's definitely worth a recommendation.
The Coles Notes: buddy buys a used copy of Majora's Mask at a yard sale. He flips it on, and it has a save file from the previous owner named "Ben." He begins his own save file, and characters in the game begin to occasionally refer to him as "Ben." He tries deleting the "Ben" file, and the game starts going off script with in-game characters doing creepy things, speaking directly to him as the player, etc.
Won't say anything further, but he also includes mash-up vids at the end of each description to show recordings of what he purports to have seen in the game. It's very entertaining.