Who's to say it's aperson? What if it is an item or a spell. Mabye it has something to do with that spell that sekret-keepers use-fedelius or what ever it was. Maybe it is a counter curse.

i think it's a lion type creature

I think he is the new DADA teacher

I think its the lion like character

i think it is a spell, but it isnt the half blood prince. Think about it, the book is entitled 'the half blood prince' do you think that jk is going to introduce the character halfway or past halfway through the book? no, she will introduce it 1/4 through. people might say that the chapter might not be introducing him, but just something about him. well the title doesnt sound like that. the title sounds like it is introducing him. i would think that it isnt introuducing him if it was like ' the perils of felix felicis" or something like that.

I think its the lion-type person, and i also think its possible that he is an animagus, but probably unlikely.

i'm leaning towards crookshanks but I doubt that is even close

I am almost 100% positive that it's not a person but a spell!

I voted for the new DADA teacher. At first I thought it was a spell but Felix is a name

i think it is lion-type character

i voted for a charm/spell.. when i was first heard of it, it seemed like a charm/spell to me... but i support those who say it's a person, since it makes perfect sense

i seriously think it is a spell. seems so likely to be so.

sorry i posted in here again... i accidently clicked the post reply sign twice oops!

To me, it seems like Felix would be the new MoM. JK has already stated that it wouldn't be Mr. Weasley, and I don't see who would take that place besides some new character. And is it just me... or are all the important characters besides the trio... ((Like teachers and stuff)) names start with the same letter? Like Minerva McGonnagall and Severus Snape. So I guess my second choice would have to be the new DADA teacher.... Hm... Choices choices.....

Akako

I think that it is a great possibility that he will be the new DADA teacher or the MoM. It doesn't really sound like a spell, and JKR said there would be a new character. So, it must be one of the two.

oo that's a good thought!

I think he will be that lion man who is the DADA teacher

my friend says its hermaiys new bf
lol

It sounds like a cat name or something. But I voted that he was the DADA teacher.

the lion-type character described by JKR earlier --> this is the HBH, I am a 99% sure. So unless Felix Summerbee is the HBH. Nop. He is probably the new Minister of Magic or another more unimportant (as unimportant as it might be in the HP world) new character.

I think it's a cheering charm, or possibly a potion...

In my opinion it can be a new member of Ordex of the Phoenix

well all this debting will be settled july 17th, i personal think its a spell

This may be stretching it, but...
Felix Felicis can be translated from latin into "lucky cat." We know of only one cat in the series, Crookshanks.
"He looked rather like an old lion. There were streaks of grey in his mane of tawny hair and his bushy eyebrows; he had keen yellowish eyes behind a pair of wire-rimmed spectacles and a certain rangy, loping grace even though he walked with a slight limp." This is an excerpt from HBP. Now, lets look at Crookshanks' details. He has orangish color fur. Tawny means a light brown to orange color. Crookshanks has yellow eyes, so does this mystery character. Crookshanks also has bowed legs, which might create a limp if he were human. Crookshanks is not just a cat, he is a "Half Blood" between a cat and a kneazle.
You must also look at the placement of the name of this character. It is the title of a chapter, which means this is a relatively important character. I dont think it is the DADA teacher nor the MoM, because you would most likely meet them in an earlier chapter. It could of course be a charm or spell, perhaps it has something to do with Crookshanks being turned into a human making him "lucky" considering he is so human-like as a cat. Whatever the case, this is my theory. We just all have to remember that JKR always has a card up her sleeve, so chances of us figuring it out are slim to none.

Since I've never heard of him.. until JK mentioned him.. I'm going with DADA professor