I am looking for a specific Harry Potter fan-fic anyone able to help?

The story is where Harry has defeated Voldamort, but Snape was believed to be kill, when reality he is a king scorpion. He ends up trailing after Harry as a familiar and protects him against a left over death eater. Can anyone tell me if they know this one, I can't remember the name, or site, any help is greatly welcome thanks, oh and the end part may contain slash, and I can't remember if the headmaster died or not