Interesting Idea about Fawkes being snape, but what about Fawkes going into the flame at DD funeral? I also wonder about the Phoenix coming from the ashes in book 2 when Harry is in DD's office. Do animagus's grow old? I don't know, but it is very interesting. The song part about the incantation has me though, authors never write something without it having a purpose. I just don't think that snape is an animagus of a Phoenix.