Supernatural Rise of the Guardians Crossover
Characters: Garth Fitzgerald IV and Toothiana (aka Tooth)
Plot line: slight spoiler from season 8 of supernatural... basically this is the story of how Garth killed the tooth fairy.
Garth used to be a dentist before he became a hunter, he still remembers is first kill, which was the tooth fairy of all things. He still remembers now it happened and it was kind of accidental as well. He was working late one night and something strange came into the surgery.
It took a bit to see it at first, but it was like human sized and covered in feathers, and chattering happily about some teeth it had found with a number of little humming bird like creatures. He kind of shot first and asked questions later. It wasn't until after he had killed it did he realize what, or rather who he had just killed. The tooth fairy. The little humming bird like creatures scatterd, and Garth actually took the body and buried it in the woods just outside of the town where he lived.
Killing the tooth fairy had not been his proudest moment. But it was his starting point as a hunter, which still counted for something.