WARNING! Spoiler alert for HBP...

If you read a chapter called 'Horcruxes' after you have read Harry-is-a-horcrux theories, you look at it in a different light. That's because a mind of a Harry Potter Analysist always thinks like a Harry Potter Analyst regardless of how much she denies it. Yes, I said I wouldn't theorize anymore but I just can't resist!

In the chapter called 'Horcruxes', Dumbledore tells Harry that Voldemort was one horcrux short when he attacked Godric's Hollow at Halloween. Voldemort had the intention of killing Harry thus making his final horcrux. First let's make an organized list of known horcruxes shall we?

Known horcruxes...
1. Voldemort himself
2. The Slytherin necklace stolen by RAB
3. The Slytherin ring - destroyed by Dumbledore
4. The Riddle diary - destroyed by Harry

Speculated horcruxes...
5. An item belonging to Gryffindor or Ravenclaw
6. The snake, Nagini
7. Helga Hufflepuff's cup

According to Dumbledore, snake Nagini only became a horcrux after his ressurection. Meaning, on Voldemort's first destruction, he had only 6 existing horcruxes - providing Dumbledore is right about the object belonging to Ravenclaw/Gryffindor.

Now, there are many Harry-is-a-horcrux theories out there. I agree with most of them. And yes, I do believe that there is a high possiblity that Harry is indeed a horcrux. An accidental one.

Right now, we are leaving facts and going into the world of mindless speculation. Enter my pensieve...

On the night that Voldemort attacked Godric's Hollow, he had intended to make his last horcrux. This is means that on that particular night, there was an object he intended to make a horcrux with him. And this also proves that the object might still be in Godric's Hollow hence why Harry will return to Godric's Hollow next year.

But fact is fact. And a horcrux is created by the death of someone. And no one died except for James and Lily - both before the intended horcrux murder.

This brings me into my very crazy wild guessing....

When Voldemort attacked Harry with the killing curse, it was meant to kill him. What happened was that the curse bounced back to hit Voldemort. This means that there was a killing curse shot at Voldemort but Voldemort having had horcruxes didn't die.

Now, assuming that the act of killing and the act of making a horcrux is very much connected, let's look at it from a reaction point of view.

Voldemort tries to kill Harry. Reverse: Harry "kills" Voldemort (but Voldemort doesn't die because of his other horcruxes). Voldemort tries to make a horcrux through killing Harry. So reversibly, it would be Harry makes horcrux through Voldemort's death.

To create a horcrux you need to kill. And Voldemort in his own words was not killed but rather, "ripped apart".

This could be that there is a unique horcrux residing in both Harry and Voldemort. Seeing as how the death of Voldeort was highly unnaturnal, it could be that this horcrux that is tied to the act of killing that night is equally as unnaturnal. Unnaturnal in what way? I do not know. Perhaps in connection to his scar who surpisingly enough, Rowling rarely mentions.

The infamous lightning bolt scar has been mentioned since the very first book and yet in reading HBP, we would almost have forgotten that Harry Potter has a lightning blot scar! Perhaps the scar has more of a role to play as Dumbledore has highlighted it's yet-to-be-discovered importance. What is the result of this unusual horcrux creating ritual gone wrong?

Do you understand anything I've said?

"Voldemort singled you out as the person who would be most dangerous to him - and in doing so, he made you the person who would be most dangerous to him." ~ Dumbledore.

So what could this possibly mean? Dumbledore said that Harry is still too young to understand how "unusual" he is...

So what happens IF Voldemort, who is Harry's horcrux tries to kill Harry, who is Voldemort's horcrux? This would explain a lot of things like the unusual mindlink between Voldemort and Harry, the matching wand cores of both Voldemort and Harry, and even the reverse spell effect which I really think there is more to than just sharing wand cores...

After all, neither can live while the other survives... and that is the crucial part of the prophecy that we have yet to investigate.