User blog comment:SayuriDarling/The House of Hades Official Discussion/@comment-4503464-20131107130909/@comment-6092594-20131111215408

It is poison. If it said it turned to poison and then Percy deflected it, then it means that it was already poison. To be honest, I didn't remember that part either. RR didn't seem to make it that clear when I read the book the first time.