[quote=-AcE-]
I don't really remember...I need to reread the series again haha But I believe that Snape created that spell himself and wrote it down in his old potions textbook...
[/quote]

Wrong spell Ace. That's [url=http://harrypotter.wikia.com/wiki/Sectumsempra]Sectumsempra[/url]

[url=http://harrypotter.wikia.com/wiki/Snake_Summons_Spell]Serpensortia[/url] Is a snake summoning spell xP